AMD’s 780G chipset

I’ve had a computer hooked up to my television for as long as I’ve had a living room. What would eventually be called a home theater PC had humble beginnings, starting its life tasked with simply playing movies and MP3s before eventually morphing into a personal video recorder and an occasional game box. Before long, living room gaming duties were offloaded to consoles, allowing years to pass with nary an upgrade to my media PC. So long has it been since I last cracked the case that a thin blanket of dust has draped itself across the system’s internals, making the now-vintage hardware look all the more old and decrepit.

The HTPC market has exploded since I last built one. What was once an expensive accessory confined to enterprising geeks and do-it-yourself enthusiasts has moved into mainstream living rooms. And thanks to the relatively modest requirements of multimedia playback and recording, even today’s budget hardware is up to the task—hardware like AMD’s new 780G integrated graphics chipset.

The latest fruit borne of AMD’s purchase of ATI packs a DirectX 10-compliant graphics core pulled from a Radeon HD 2400 graphics card, decode acceleration for HD DVD Blu-ray movie playback, second-generation PCI Express, Hybrid CrossFire, a new SB700 south bridge, and a Phenom-ready HyperTransport 3 processor link. All that’s coming to motherboards that should cost less than $100. Alongside it, AMD is introducing a new energy-efficient Athlon X2 4850e with a 45W TDP and $89 price tag.

On paper, it looks like we have the recipe for a killer home theater PC or mainstream desktop. But has AMD nailed the execution this time around? We’ve run the 780G and 4850e through a grueling array of tests in order to find out.

New hotness all around

The 780G is a new chipset from its integrated graphics processor through the north bridge and all the way down to the south bridge. Of those components, the IGP is perhaps the most exciting. Dubbed the Radeon HD 3200, the integrated graphics core is ripped directly from the RV610 graphics processor that powers the Radeon HD 2400 series—a chip that was released just eight months ago. That’s incredibly quick trickle down from budget GPU to integrated graphics chipset, making this the first IGP we’ve had that’s really in step with the current generation of discrete GPUs.

Because it’s a member of the same graphics family as AMD’s discrete GPUs, the Radeon HD 3200 is also eligible for Hybrid Graphics configurations. The chipset’s GPU can be teamed with a single graphics card—in this case either a Radeon HD 3450 or 3470—to improve performance in 3D applications. Hybrid CrossFire only delivers performance gains when GPUs of relatively similar horsepower are combined, which is why the Radeon HD 3200 IGP will only work in conjunction with the HD 3400 series of discrete GPUs.

Within the integrated Radeon HD 3200 graphics processor lies a unified shader architecture that spreads 40 stream processors across two shader SIMDs. Also included are single texture and ROP units capable of handling four texels and pixels per clock, respectively. The vertex and texture caches are shared to save die area (they’re separate with most other R600-based designs), but the Radeon HD 3200 is still very much a DirectX 10-class part. If you think of the new Radeon HD 3800 series as a V8, the 3200 is essentially a single piston—one that runs at an impressive 500MHz and has access to up to 512MB of system memory.

Thanks to the 780G north bridge chip’s HyperTransport 3 link, which scales up to 1.8GHz with AMD’s current Phenom processors, the Radeon HD 3200 enjoys a very fat pipe to two channels of DDR2 memory at up to an effective 1066MHz. Motherboard makers can also equip the 3200 with dedicated memory of its own, an addition that AMD says can improve performance by 10-15%. Such support for local memory in an IGP isn’t actually new, but it’s a capability rarely exploited by motherboards that show up in retail. AMD claims tier-one mobo makers are, er, onboard to take advantage of it this time around, though.

The 780G block diagram. Source: AMD

HyperTransport bandwidth is apparently so important to the Radeon HD 3200 that AMD recommends a 1.8GHz link—currently available only with Phenom—to make the most of the graphics core. The 3200’s post-processing engine for high-definition video playback actually requires the 1.8GHz HT link that Phenom provides. You don’t need a Phenom to take advantage of the Radeon HD 3200’s other video decoding capabilities, though. The integrated GPU’s enhanced Universal Video Decoder (UVD) block is capable of handling decoding duties for high definition Blu-ray movies, and if you’re a fan of the new Betamax, it’ll do HD DVD too.

High-definition-ness is carried all the way through to the HD 3200’s outputs, which include not only VGA and DVI, but also HDMI and even DisplayPort. HDCP is supported, as well, and the 780G is smart enough to be able to route S/PDIF audio through its HDMI output.

We’ve spent a lot of time on integrated graphics, but it’s not the only element of the 780G’s new hotness. The north bridge also gets 26 lanes of second-generation PCI Express connectivity, should you want to add a discrete graphics card of your own. 16 of those lanes are reserved for an x16 link, while six are distributed across x1 links meant for expansion slots and onboard peripherals. The remaining four links are reserved for the chipset’s north bridge-to-south bridge interconnect.

Follow the interconnect south, and you’re greeted by AMD’s eagerly-anticipated SB700 south bridge chip, which ultimately arrives with a bit of a whimper. The SB700 may be new silicon, but in many ways, it’s just more of the same. Take the chipset interconnect, for example. The 780G has four lanes of PCIe 2.0 reserved for its chipset link, and while the SB700 can match its northern neighbor’s lane count, those PCI Express lanes come from the previous 1.1 generation. This caps north-south bridge interconnect bandwidth at 2GB/s—half of what it could have been with a top-to-bottom PCIe 2.0 implementation.

We quite literally see more of the same in the SB700’s Serial ATA controller. The port count here is up to six, but they’re basically six of the same ports you get on the old SB600. Drives can be configured in RAID 0, 1, and 10 arrays, but RAID 5 remains unavailable. This omission is notable because if you’re a little paranoid about data loss, a three-drive RAID 5 might be a decent solution for a home theater PC.

On the USB front, the SB700 is up to 12 ports, this time with a dual-channel controller AMD says is faster than what can be found in the SB600. A couple of USB 1.1 ports are also included, apparently at the request of notebook makers who use them for various widgets.

The prospect of 780G notebook applications leads us nicely to the chipset’s party piece: its power consumption. A very advanced—at least in chipset terms—55nm fabrication process is used to manufacture the chipset’s north and south bridge components, bringing idle power consumption for the chips down to what AMD claims is less than one watt each.

Gigabyte’s GA-MA780GM-S2H mobo
780G in the flesh

Manufacturer Gigabyte
Model GA-MA78GM-S2H
Price (Street)
Availability Now

The 780G chipset arrived in our labs riding aboard Gigabyte’s new GA-MA780GM-S2H motherboard. You can already find this board for sale online, albeit from only one vendor at the moment. Still, it’s selling for roughly $100, which is quite affordable considering the board’s payload of features and the fact that it’s such a fresh release.

As one might expect, the GA-MA780GM-S2H continues Gigabyte’s tradition of entirely too long and convoluted motherboard names. The board is built for a Micro ATX form factor that will squeeze nicely into smaller enclosures while still providing a couple of PCI and PCI Express expansion options, including an x16 slot if you want to skip out on the chipset’s integrated graphics or take advantage of its Hybrid CrossFire capability.

Gigabyte’s board designers have done a reasonably good job with the board’s layout given the Micro ATX form factor’s restrictive dimensions. Longer double-wide graphics cards will block access to some of the SATA ports, but that’s hard to avoid when there’s limited board real estate to work with.

At least the board’s chipset coolers won’t get in the way. Low-profile heatsinks cover the chipset’s north and south bridge components with nary a fan in sight, which bodes well for this motherboard’s suitability for silent desktops and home theater PCs. Such modest cooling also reflects well on the 780G’s power consumption.

Around the port cluster, the Gigabyte board packs an impressive array of video outputs. You won’t find any DisplayPort goodness here, but VGA, DVI, and HDMI ports are all present. There’s also an S/PDIF audio output courtesy of one of Realtek’s swanky ALC889A codec chips. The ALC889A is about as high-end as Realtek’s HD audio codecs get; it actually supports DTS Connect encoding that allows users to pass multi-channel audio over a single digital connection.

Firewire and External Serial ATA connectors make an appearance in the port cluster, as well, with the latter fed by the same SB700 south bridge the powers the internal SATA ports. Four USB ports are also provided, alongside onboard headers for eight more. And, of course, there’s a single Gigabit Ethernet port. Since the 780G lacks integrated networking, GigE duties are handled by a Realtek 8111C networking controller that happily sits on the PCI Express bus.

One more thing

To coincide with the 780G chipset launch, AMD is taking the wraps off its new Athlon X2 4850e processor. Fabbed on a 65nm process, the 4850e has the same 2.5GHz clock speed and 1MB L2 cache as the Athlon X2 4800+, but with a TDP of just 45 watts.

The 4850e isn’t available online just yet, but AMD says the chip will sell for only $89. That’s essentially the same price as the existing Athlon X2 4800+, so the new chip’s lower power consumption won’t cost you any extra. AMD is adamant that performance is consistent between the two chips, as well.

Asus’ P5E-VM HDMI motherboard
Introducing the G35 Express

Manufacturer Asus
Model P5E-VM HDMI
Price (Street)
Availability Now

With Nvidia’s next-gen GeForce 8200 integrated graphics chipset not quite ready for prime time, the 780G’s primary competition will come from Intel’s G35 Express. This latest IGP chipset from the blue team features a GMA X3500 graphics processor with a unified shader core whose roots can be traced all the way back to the GMA X3000 found in the G965 Express chipset. Like the X3000, the X3500 has eight scalar shader execution units and a 667MHz core clock speed. The X3500 is DirectX 10-compliant, too, with support for Shader Model 4.0 and OpenGL 2.0. This IGP also packs a Clear Video decode engine that can offload some elements of the HD video playback process.

The G35 Express is more of a refresh than a brand new chipset, though, and it shows. Digital video outputs like DVI and HDMI are only supported through auxiliary sDVO (Serial Digital Video Output) chips, and PCI Express is limited to gen-one connectivity. Intel’s block diagram for the G35 even calls for the chipset to include south bridge components from the old ICH8 family.

Asus has been a little more enterprising with its G35-based P5E-VM HDMI, pairing the G35 Express north bridge with the very same ICH9R south bridge chip you’ll find on high-end P35 and X38 boards. The result is a Micro ATX motherboard with many of the bells and whistles one might expect from a full-size ATX model.

The P5E-VM uses a much larger north bridge cooler than we saw strapped to the 780G, but it’s still a fanless and therefore silent design. Asus favors PCIe over PCI, equipping the board with a pair of PCIe x1 slots and only a single PCI slot. That actually makes sense given the fact Asus is now making PCI Express sound cards.

Installing a double-wide graphics card will cost you one of the x1 slots, though. Longer double-wide cards will also interfere with a number of the board’s SATA ports—apparently par for the course within the Micro ATX form factor’s relatively cramped proportions.

In fact, the board is so crowded that Asus has moved a handful of components onto a little riser card that sits just above the top PCIe x1 slot. This card houses an ASMedia Technology ASM4136 chip, which according to what little information is available on the wide world internets—and then mostly in speculative forum discussions—is some sort of video processing decoder likely tied to the board’s HDMI output.

You won’t find quite the bounty of ports on the P5E-VM that we did on the Gigabyte board, but there’s plenty to like here, including VGA and HDMI video outputs. DVI output is supported, as well, although only through an HDMI-to-DVI adapter that Asus includes in the box. The board has a full range of analog audio outs and a coaxial S/PDIF output courtesy of Realtek’s budget ALC883 codec.

As one might expect, the P5E-VM features Gigabit Ethernet, but through an PCIe-based Atheros L1 networking controller rather than more common chips from Marvell or Realtek. Firewire and USB make the cut, as well, but External Serial ATA is conspicuously missing.

What’s in a Micro ATX BIOS?

Micro ATX models are rarely revered for their tweaking and overclocking options, so we poked around the BIOSes for our Asus and Gigabyte boards to see what we could find. Much to our surprise, these boards are pretty well equipped if you want to get your hands dirty and fiddle around.

Asus P5E-VM HDMI Gigabyte GA-MA78G-S2H

Bus speeds
FSB: 400-800MHz in
1MHz increments
FSB strap: 200, 266, 333MHz

PCIe: 100-150MHz in 1MHz increments

DRAM: 533, 667,
800MHz

HT:
200-500MHz in
1MHz increments
HT Link: 200MHz-2.6GHz in 200MHz increments

PCIe: 100-200MHz in 1MHz increments

VGA core: 150-1100MHz in 1MHz increments


Bus multipliers
CPU: 6x-10x (Pentium E2180) CPU: 5x-25x (Phenom 9600 BE)

DRAM controller frequency: 5x-16x

DRAM: 2,2.66,3.33,4,5.33

Voltages CPU: 1.1-1.7V in 0.0125V increments

DRAM: 1.8-2.44V in 0.02V increments

PLL: 1.5-1.8V in 0.02V increments
FSB termination: 1.2-1.5V in
0.02V increments
NB:
1.25-1.71V in 0.02V increments
SB: 1.05, 1.2V

CPU: +0.025-0.6V in 0.025V increments

DRAM: +0.1-0.3V in 0.1V increments

NB: +0.1-0.3V in 0.1V increments


Monitoring
Voltage, fan
status, and temperature monitoring
Voltage, fan
status, and temperature monitoring

Fan speed control
CPU, chassis CPU

Both offer all the usual memory timings with a decent array of overclocking options, to boot. Front-side bus and HT clock speeds are available in ranges that should be more than ample for most folks. You can even tweak CPU and chipset voltages, although there are more overvolting options on the Asus board than on the Gigabyte.

Temperature-based processor fan speed control is really a must-have feature for home theater PCs, so it’s good to see it making an appearance in both BIOSes. The Asus board offers temperature-based fan speed control for its system fan header, which is a nice little perk. Neither board exposes BIOS-level control over target temperatures or fan speed profiles, though.

If you’re planning on plunking a Phenom into the GA-MA78GM-S2H, you’ll be happy to know that its latest F3C BIOS revision includes a switch to disable AMD’s TLB workaround. AMD has instructed motherboard makers not to include such a switch in their BIOSes, but Gigabyte and others don’t appear to be heeding that request, which suits us just fine. You should also be able to disable the TLB patch using AMD’s OverDrive software, which is fully compatible with the 780G chipset.

Specifics on specifications

To cover all the little details we haven’t had the chance to discuss yet, I’ve compiled a handy spec sheet that sums up the Asus P5E-VM HDMI and the Gigabyte GA-MA78GM-S2H.

Asus P5E-VM HDMI Gigabyte GA-MA78G-S2H

CPU support
LGA775-based
Celeron, Pentium 4/D, Core 2 processors
Socket AM2+/AM2-based Athlon,
Phenom processors

North bridge
Intel G35 Express AMD 780G

South bridge
Intel ICH9R AMD SB700

Interconnect
DMI (2GB/s) PCI Express x4 (2GB/s)

Expansion slots
1 PCI Express x16

2 PCI Express x1
1 32-bit/33MHz PCI

1 PCI Express x16

1 PCI Express x1
2 32-bit/33MHz PCI


Memory
4 240-pin DIMM
sockets

Maximum of 8GB of DDR2-667/800/1066 SDRAM

4 240-pin DIMM
sockets

Maximum of 16GB of DDR2-667/800/1066 SDRAM


Storage I/O
Floppy disk

1 channel ATA/133 via JMicron JMB368

6 channels 300MB/s Serial ATA with RAID 0, 1, 10, 5 support

Floppy disk

1 channel ATA/133

5 channels 300MB/s Serial ATA with RAID 0, 1, 10 support

Audio 8-channel HD audio via Realtek ALC883 codec 8-channel HD audio via Realtek
ALC889A codec
Ports 1 PS/2 keyboard
1 PS/2 mouse
1 VGA
1 HDMI

6 USB
2.0 with headers for 6 more

1 RJ45 10/100/1000 via Atheros L1
1 1394a Firewire via
VIA VT6308P with header for 1 more

1 analog front out
1 analog bass/center out

1 analog rear out

1 analog surround out

1 analog line in

1 analog mic in
1 digital coaxial S/PDIF
output

1 PS/2 keyboard
1 PS/2 mouse
1 VGA
1 DVI
1 HDMI
1
eSATA

4 USB
2.0 with headers for 8 more

1 RJ45 10/100/1000 via Realtek 8111C
1 1394a Firewire via
Texas Instruments TSB43AB23 with header for 1 more

1 analog front out
1 analog bass/center out

1 analog rear out

1 analog surround out

1 analog line in

1 analog mic in
1 digital TOS-Link S/PDIF
output

There isn’t much to see here, although it is worth noting that the Gigabyte board claims to support up to 16GB of memory. We don’t even want to know how much a 4GB DIMM is going to cost you, though. Suffice to say it’s probably several times that of the motherboard itself.

Notice that Asus and Gigabyte differ in their choice of Firewire providers. Asus chose VIA’s VT6308P, while Gigabyte opted for a Texas Instruments chip. We’ll see in a moment how the performance of these two implementations compares.

Our testing methods

With the 780G and Athlon X2 4850e launching on the same day, we thought it appropriate to test the two together as a low-cost integrated graphics platform. To fill out our G35 Express board, we have a dual-core Pentium E2180 that costs about as much as the 4850e should when it touches down on store shelves. Do keep in mind that our G35-based Asus board, which seems to be the only G35 offering widely available in North America, costs $30 more than Gigabyte’s 780G board. Integrated graphics motherboards based on AMD chipsets have traditionally cost less than those from the Intel camp.

We conducted all of our performance testing with the boards running their integrated graphics. Additional game tests were run with a Radeon HD 3450 graphics card on each board and in a Hybrid CrossFire configuration with the 780G.

All tests were run three times, and their results were averaged.

Processor

Intel Pentium E2180 2.0GHz
AMD Athlon X2 4850e
System bus 1066MHz (266MHz
quad-pumped)
1GHz HyperTransport
Motherboard

Asus P5E-VM HDMI


Gigabyte GA-MA78GM-S2H
Bios revision 0405 F3C
North bridge Intel G35 Express AMD 780G
South bridge Intel ICH9R AMD SB700
Chipset drivers Chipset 8.3.1.1009
AHCI 7.8.0.1012
IGP 15.7.3
Chipset/IGP 8.470.0.0
AHCI
3.1.1540.38
Memory size 2GB (2 DIMMs)
Memory type
Corsair
TWIN2X2048-8500C5

DDR2 SDRAM at
800MHz

Corsair
TWIN2X2048-8500C5

DDR2 SDRAM at
742MHz
CAS latency
(CL)
4 4

RAS to CAS delay (tRCD)
4 4
RAS precharge
(tRP)
4 4
Cycle time
(tRAS)
12 12
Audio codec Realtek
ALC883
with 1.87a drivers
Realtek
ALC889A
with 1.87a drivers

Hard drive


Western Digital Raptor WD1500ADFD 150GB
SATA

OS


Windows Vista Ultimate x86

OS updates
KB936710,
KB938194, KB938979, KB940105

Thanks to Corsair for providing us with memory for our testing. 2GB of RAM seems to be the new standard for most folks, and Corsair hooked us up with some of its 1GB DIMMs for testing.

All of our test systems were powered by OCZ GameXStream 700W power supply units. Thanks to OCZ for providing these units for our use in testing.

Finally, we’d like to thank Western Digital for sending Raptor WD1500ADFD hard drives for our test rigs. The Raptor’s still the fastest all-around drive on the market, and the only 10K-RPM Serial ATA drive you can buy.

We used the following versions of our test applications:

The test systems’ Windows desktop was set at 1280×1024 in 32-bit color at an 85Hz screen refresh rate. Vertical refresh sync (vsync) was disabled for all tests.

All the tests and methods we employed are publicly available and reproducible. If you have questions about our methods, hit our forums to talk with us about them.

Memory performance

Memory subsystem performance doesn’t always track with real-world applications, but it’s a good place to start with integrated graphics chipsets that cannibalize a portion of system memory and therefore bandwidth.

The Athlon X2’s integrated memory controller works wonders here, providing heaps more bandwidth and much lower access latencies than Intel’s G35 Express.

Memory controllers don’t always handle four DIMMs gracefully, so we popped an additional two memory modules into each system for another round of tests.

With a full complement of memory modules installed, the performance picture really doesn’t change much. The 780G platform is way out ahead again, and it actually offers better memory performance with four DIMMs installed than with two. By contrast, our G35 boards offers a little less bandwidth and higher access latencies when we fill its DIMM slots.

The following latency graphs are a little indulgent, so I won’t be offended if you skip them. They show access latencies across multiple block and step sizes, painting a fuller picture of memory controller performance with each chipset. I’ve arranged the graphs in order of highest latency to lowest. Yellow represents L1 cache, light orange is L2, and dark orange is main memory.

Our G35 system’s Pentium E2180 processor may have a bigger L2 cache than the 780G’s Athlon X2 4850e, but as we move to block sizes that spill over into main memory, the AMD platform’s significantly lower access latencies come into play in dramatic fashion.

STARS Euler3d computational fluid dynamics

Few folks run fluid dynamics simulations on their desktops, but we’ve found this multi-threaded test to be particularly demanding of memory subsystems, making it a good link between our memory and application performance tests.

Despite scoring better in our memory subsystem tests, the 780G actually lags behind the G35 Express in Euler3d. Keep in mind, of course, that these rival platforms are backed by entirely different processor architectures.

WorldBench

WorldBench uses scripting to step through a series of tasks in common Windows applications. It then produces an overall score. WorldBench also spits out individual results for its component application tests, allowing us to compare performance in each. We’ll look at the overall score, and then we’ll show individual application results alongside the results from some of our own application tests.

The 780G is two points off the pace set by the G35 Express in WorldBench. Can it steal a win in any of the suite’s individual application tests?

Not through WorldBench’s multimedia editing and encoding apps, which show the G35 Express consistently ahead. The gap in Photoshop performance is particularly striking

However, the 780G makes some headway with WorldBench’s Firefox and multitasking test, topping the G35 twice.

And twice more through WorldBench’s 3ds max tests. Here we get our first look at integrated graphics performance, with the 780G finishing the DirectX test in nearly half the time it takes the G35.

Nero and WinZip favor the G35 platform, though. These tests have shown themselves to be more sensitive to disk controller performance than the others, suggesting that SB700 may have to shoulder some of the blame here.

Gaming

We’ve had more than one game developer decry integrated graphics as the bane of their existence, and it’s easy to see why. With today’s latest titles, you have to back off most in-game detail levels and drop the resolution way down to get frame rates that are even close to what we’d consider playable. Crysis just isn’t the same with a low graphics detail setting, and the others don’t look so hot, either.

But I suppose it’s impressive that an IGP can run such recent titles at all. Even the G35 Express managed to slog through Crysis without obvious visual artifacts, although it inexplicably wouldn’t launch the multiplayer component of Call of Duty 4 necessary to run our custom timedemo. The P5E-VM had problems with CoD 4 with a Radeon HD 3450 graphics card, as well, and not even reinstalling the game would get it to launch in Vista.

Note that we have several sets of results here. Naturally, we’ve tested the 780G and G35 with their integrated graphics. Both platforms were also tested with a discrete Radeon HD 3450 graphics card. The 780G was also tested in a Hybrid CrossFire configuration with the Radeon. Finally, we’ve thrown in some results with the 780G’s integrated graphics backed by the 1.8GHz HyperTransport link offered by a Phenom 9600.

The first thing to take away from these results is just how completely the 780G’s integrated graphics core outclasses the G35 Express. Settings that deliver reasonably playable framerates on the 780G reduce the G35 to little more than an embarrassing slideshow. Throw in a Radeon HD 3450, though, and the 780G and G35 are well matched. At least until you enable Hybrid CrossFire.

When we use Hybrid CrossFire to combine the integrated graphics processor’s abilities with the Radeon’s firepower, the 780G’s performance rises by a modest margin in most games.

Integrated graphics performance does improve if we add a Phenom to the equation. However, it’s hard to say how much of the framerate boost is due to the Phenom’s faster HyperTransport link rather than its additional computational prowess.

HD Video playback

With HD DVD essentially dead, we confined our video playback tests to Blu-ray movies with the highest bitrates we could find for each of the format’s three encoding types. For MPEG2 encoding, we settled on Nature’s Journey, which is packed with ridiculously gorgeous loops of nature scenes. On the AVC front (otherwise known as H.264), the highest bitrates we could get our hands on came with the fast zombie flick 28 Days Later. We had to scrape the bottom of the barrel for VC-1, eventually settling on Click. For whatever reason, an Adam Sandler comedy is encoded with a higher bitrate than other VC-1 movies.

We used PowerDVD 7.3 for playback and enabled hardware acceleration within the application. CPU utilization was logged for 60 seconds of playback with each movie, and the results were averaged. Movies were played back in fullscreen mode with the desktop resolution set to 1920×1440 to make things as difficult as possible for the IGPs.

In addition to providing results for the 780G and G35 Express, we’ve also thrown in some numbers from a Radeon HD 3450 running on the 780G platform. That should give us a good idea of how integrated solutions compare to a discrete graphics card with full decode capabilities.

Between our integrated graphics platforms, the 780G exhibits much lower CPU utilization than the G35 Express. More importantly, the AMD chipset’s playback was buttery smooth throughout. The same can’t be said for the G35 Express, whose playback of MPEG2 and AVC movies was choppy enough to be unwatchable. We only observed smooth video playback on the G35 with VC-1 content, which not-so-coincidentally also delivered the lowest CPU utilization for the Intel platform.

While the 780G’s playback prowess is no doubt impressive, we actually expected lower CPU utilization—something along the lines of what we saw with the Radeon HD 3450. Swapping in a Phenom reduced CPU utilization by a little more than half, but that’s to be expected since Phenom also doubles the number of processor cores.

HQV video quality

The HQV benchmark is a DVD designed to test the image quality of televisions, monitors, and DVD players with a series of specific feature tests. It can also be a handy tool to evaluate how a graphic’s card’s video processor handles tasks like de-interlacing, motion correction, antialiasing, and film cadence detection. We tested the standard definition version of HQV using PowerDVD 7.3.

AMD scores a perfect 130 here, nailing each and every one of the HQV tests. The G35 Express doesn’t fare as well, managing a score of only 70. I’m not entirely happy with how that score reflects the G35’s actual performance, though. HQV’s tests rely on arbitrarily subjective scoring, and in many of its tests, flickering problems on the G35 that degraded the overall viewing experience didn’t actually meet the criteria for a lower score.

Serial ATA performance

The Serial ATA disk controller is one of the most important components of a modern core logic chipset, so we threw each platform a selection of I/O-intensive storage tests using a Western Digital Raptor WD1500ADFD. Testing was conducted with the SB700 running in AHCI mode, which is necessary for Native Command Queuing, using the latest drivers supplied by AMD.

AMD’s older SB600 south bridge had numerous problems running in AHCI mode. It required a Vista hotfix to work properly, and you’d need an external storage controller to get the operating system installed. The hotfix fortunately isn’t required with the SB700. However, if you want to get Vista running in AHCI mode, you have to first install the OS in IDE mode, then swap the hard drive to an auxiliary storage controller running on the same system, switch the SB700 to AHCI mode and install the necessary drivers, and then move the hard drive back to the south bridge. It’s ridiculous to ask users to jump through hoops just to enable AHCI. AMD should have worked closer with Microsoft to prevent a documented problem with an old south bridge chip from afflicting the new SB700.

IOMeter

We’ll begin our storage tests with IOMeter, which subjects our systems to increasing multi-user loads. Testing was restricted to IOMeter’s workstation and database test patterns, since those are more appropriate for desktop systems than the file or web server test patterns.

The SB700’s Serial ATA controller really is more of the same. Like the SB600 before it, the SB700 appears to have problems scaling performance as the number of simultaneous I/O requests increases. We only tested with a single driver revision here, but it’s the latest one. Clearly, our G35 Express board’s ICH9R south bridge is doing a much better job handling IOMeter workloads.

As you can see, response times are much lower on the G35 than with the 780G, particularly as the number of simultaneous I/O requests scales up.

At least CPU utilization is reasonable for the 780G, although given its poor throughput, that’s not saying much. We’ve seen driver revisions that fix the SB600’s performance scaling problems have a detrimental impact on CPU utilization, and since the two share essentially the same SATA underpinnings, we’d expect similar results from the SB700.

HD Tach

We used HD Tach 3.01’s 8MB zone test to measure basic SATA throughput and latency.

HD Tach doesn’t hammer drives with multiple I/O requests, which suits the 780G just fine. Burst and read speeds are pretty close between the 780G and G35, with the latter pulling out ahead in the average write speed test. The write speed test is an interesting anomaly, since we’ve seen numerous chipsets that correctly support Native Command Queuing exhibit performance similar to the G35’s with our Raptor hard drive.

The 780G is a hair quicker than the G35 in HD Tach’s random access time test. We’re talking tenths of a millisecond here, so make that a fraction of a hair.

CPU utilization results are within HD Tach’s margin of error in this test.

USB performance

Our USB transfer speed tests were conducted with a USB 2.0/Firewire external hard drive enclosure connected to a 7200RPM Seagate Barracuda 7200.7 hard drive. We tested with HD Tach 3.01’s 8MB zone setting.

AMD has done well bolstering the SB700’s USB performance. The new south bridge is a little slower than Intel’s best in our burst and sustained read speed tests, but much quicker when it comes to writing, with competitive CPU utilization.

PCI Express performance

We used ntttcp to test PCI Express Ethernet throughput using a Marvell 88E8052-based PCI Express x1 Gigabit Ethernet card.

These two boards’ PCI Express GigE throughput is all but identical, although the AMD platform has an advantage in CPU utilization. The 780G system also has two cores running at 2.5GHz, while G35’s dually is clocked 500MHz slower at 2GHz.

PCI performance

To test PCI performance, we used the same ntttcp test methods and a PCI VIA Velocity GigE NIC.

I’m at a loss to explain this one, folks. For whatever reason, our G35 Express board doesn’t get along with the older VIA networking card we use for PCI throughput testing. This particular card has delivered much better performance on other motherboards that use the exact same ICH9R south bridge, so I’m more inclined to write this off as an odd motherboard incompatibility rather than a flaw in the G35 chipset. Forget about the CPU utilization results, too; with such disproportionate throughput, we can’t draw many conclusions here.

Despite the 780G’s obvious throughput lead, 650Mbps isn’t particularly impressive. We’ve seen this card pushing 730-840Mbps on other platforms, making me wonder if perhaps the SB700 has inherited its predecessor’s pokey PCI performance characteristics.

Power consumption

We measured system power consumption, sans monitor and speakers, at the wall outlet using a Watts Up Pro power meter. Power consumption was measured at idle and under a load consisting of a multi-threaded Cinebench 10 render running in parallel with the “rthdribl” high dynamic range lighting demo. Results that fall under “No power management” were obtained with Windows Vista running in high performance mode, while those with power management enabled were taken with Vista in its balanced performance mode.

Our 780G system consumes much less power at idle than its G35-based rival, particularly when Cool’n’Quiet is free to throttle the processor’s clock speed. That alone drops power consumption by eight watts, slipping our 780G rig below the 50-watt mark, and more importantly, 20 watts below the best our G35 Express platform can do. Crank up a combined CPU and GPU load, though, and the G35 Express sips five fewer watts than the 780G.

Motherboard peripheral performance

Core logic chipsets integrate a wealth of peripherals, but they don’t handle everything. Firewire and audio are farmed out to auxiliary chips, for example, and so is networking. To provide a closer look at the peripheral performance you can expect from the motherboards we’ve tested today, we’ve complied Ethernet, Firewire, and audio performance results below. We’ve used motherboard rather than chipset names here because these performance characteristics reflect the auxiliary peripheral chips used on each board rather than the performance of the core logic chipset.

NTttcp Ethernet performance

Throughput (Mbps)

CPU utilization
(%)

Asus P5E-VM HDMI

941.340

21.53

Gigabyte GA-MA78GM-S2H
944.293 18.72

GigE throughput is pretty close, with the Gigabyte board holding a small advantage in CPU utilization. Keep in mind that we’re talking about the utilization of two completely different processors.

HD Tach
Firewire performance

Read burst

speed (MB/s)


Average read

speed (MB/s)


Average write

speed (MB/s)


CPU utilization

(%)


Asus P5E-VM HDMI
32.8 28.9 21.7 0.3

Gigabyte GA-MA78GM-S2H
42.1 37.6 24.2 2.7

The Gigabyte 780G board’s Texas Instruments Firewire chip proves much faster than the VIA controller on the Asus G35 board. Burst and sustained read speeds aren’t even close between the two boards.

RightMark Audio
Analyzer audio quality

Overall score

Frequency response

Noise level

Dynamic range

THD

THD + Noise

IMD + Noise

Stereo Crosstalk

IMD at 10kHz

Asus P5E-VM HDMI
4 5 3 3 3 1
3
4
3

Gigabyte GA-MA78GM-S2H
3 5 1 1 3 1 3 4 3

RightMark Audio Analyzer favors the Asus board, although only slightly. A poor showing by the Gigabyte in RMAA’s noise level and dynamic range tests drags down its overall score.

Conclusions

AMD’s 780G integrated graphics chipset lives up to its potential, delivering an incredibly complete platform for mainstream desktops and home theater PCs within a surprisingly modest power envelope. With a little help from an energy-efficient Athlon X2 4850e, the 780G’s idle power consumption is nothing short of a revelation. And it’s not like the chipset has sacrificed features and performance in the name of power efficiency. The 780G packs in a DirectX 10-class integrated graphics core, PCI Express 2.0, loads of expansion ports and display output options, and a very impressive video decoder capable of smooth 1080p Blu-ray playback in any format, with even a budget CPU.

In addition to its potent video decoding capabilities, the 780G’s Radeon HD 3200 graphics core offers the best 3D performance we’ve seen from an IGP—not that we expected any less from what is essentially an eight-month-old budget GPU squeezed into the 780G’s north bridge. Never before has integrated graphics come this close to delivering the kind of experience you get with a discrete graphics card.

That said, the experience still isn’t close enough if you want to play the latest games and have them look even remotely like they’re supposed to. We had to drop resolutions all the way down and scale in-game detail levels way back just to get playable frame rates. Hybrid CrossFire helped, but it didn’t do enough. The 780G’s graphics core may beat Intel’s GMA slideshow by miles, but if you want to really experience games, we recommend biting the bullet and buying a proper graphics card.

The 780G’s case is further helped by Gigabyte’s excellent implementation in the GA-MA78GM-S2H. You get a lot of board for only $100, including passive chipset cooling, a great array of expansion ports, a fast Firewire chip, and surprisingly decent BIOS tweaking and overclocking options. Gigabyte even throws in a switch to disable AMD’s TLB erratum patch should you wish to drop a Phenom into the board without incurring a severe performance penalty.

The 780G isn’t perfect, though, and our enthusiasm for the chipset is tempered by an SB700 south bridge that feels more like a die-shrunk SB600 than a brand new chip. The fact that AMD has allowed AHCI problems that afflicted the SB600 to persist in the SB700 comes across as more than just a little sloppy, particularly given the hoops one has to jump through just to install Vista in AHCI mode. Mainstream desktops and home theater PCs may see little benefit from the Native Command Queuing support that AHCI mode provides, but it’s a feature that should work properly. And it just doesn’t.

Even through it falls short of perfection, AMD’s 780G is still the best integrated graphics chipset we’ve ever tested and a perfect platform for do-it-yourself home theater PCs. Intel’s integrated graphics performance just doesn’t measure up, and while Nvidia’s upcoming GeForce 8200 should provide stiffer competition, it’s not ready yet. You can buy Gigabyte’s 780G board today.

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pmshah
pmshah
13 years ago

This might be a bit late for this particular thread but this is the problem I encountered under Windows XP SP3. I have a USB connected 4 port KVM switch. Keyboard and mouse are PS2. On a MSI – K9A2GM-FIH motherboard sporting SB700 chipset, invariably either the keyboard or the mouse are not recognised. Quite often neither is recognised. I have to resort to resetting the KVM to gain access to the PC. Another problem I face is using a 16GB Kingston Traveler pen drive. It ALWAYS gives an error, even in reading. MSI is clueless in finding a solution… Read more »

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