SiS’s 648 chipset

TODAY SIS IS OFFICIALLY letting loose its new 648 chipset for the Pentium 4, and we’re welcoming it by testing the 648 against six of its closest competitors in a total of 11 different configurations.

Yes, our skin is pasty white, and sunlight hurts our eyes.

But you get to benefit! We’ll show you just how this new chipset contender, which packs a wallop with AGP 8X and unofficial DDR400 support, stacks up.

Introducing the 648 chipset
The 648 chipset has nearly every one of the latest features you might want in a new chipset. The 648 north bridge chip has a revamped AGP interface with AGP 8X support and—surprise!—twice the bandwidth of AGP 4X solutions. The front-side bus supports the latest Pentium 4 chips with 533MHz bus speeds. And the reworked memory controller is faster than in the 645/645DX chipsets, with the ability to host three DIMMs of DDR266 memory or two DIMMs of DDR333. Unofficially, the 648 will support DDR400, as well—the necessary bus-to-memory clock ratio is there, and it worked flawlessly in our tests with a single stick of Corsair DDR400 memory. (When the time comes, I expect SiS to release a “648DX” chip that’s unchanged in silicon but has official support for DDR400.)

The 648 north bridge chip

In between the 648 north bridge and the new 963 south bridge chip is SiS’s proprietary MuTIOL chipset interconnect. This 16-bit interconnect runs at an effective rate of 533MHz, delivering a total of 1GB/s of bandwidth. That’s twice the speed of VIA’s “Enhanced V-Link” and four times as fast as Intel’s Accelerated Hub interconnect.

Source: SiS

The extra bandwidth will be needed, because SiS’s new 963 south bridge chip can push a whole lotta bits at once. The chip supports up to six USB 2.0 ports at 480Mbps a pop, plus three IEEE 1394a (also known as Firewire) ports at 400Mbps each. The 963’s updated disk controller can support dual ATA/133 channels, as well. Like its predecessors, the 963 also supports the full range of south bridge three-letter acronyms, including PCI, LPC, and ACR. The PCI controller can sustain six PCI master devices at once.

The 963 south bridge chip handles I/O duties

The AC’97 audio built into SiS’s 735/745 chips for the Athlon sounded much cleaner to my ear than, say, VIA’s south bridge audio. This time out, SiS has added more AC’97 channels, so the 963 can support six channels of audio plus a V.90 modem. (Yep, AC’97 is also used in chipsets for modem support.) As a result, the 963 can drive 5.1-channel surround audio speaker systems, if mobo makers choose to implement all six channels of SiS AC’97 sound.

All told, these feature additions and updates give the 648 chipset nearly every cutting-edge feature one could imagine, with a few possible exceptions like Serial ATA. In short, the 648 is loaded.

What about the P4X400?
Since we’ve included results for the VIA P4X333 chipset below but not the new P4X400, I should explain a few things. First, the P4X333 is one of the oddest (and least vaporous) cases of vaporware I’ve seen. VIA sent us a P4X333 reference board for testing with a PR rep attached, and we proceeded to review the chipset in anticipation of P4X333-based products hitting the market soon. Yes, there’s an ongoing legal fight between VIA and Intel, but VIA itself and key partners like Shuttle were selling VIA-based Pentium 4 boards regardless. The chipset performed well, and our review was fairly positive as a result.

Weeks passed. Readers wrote us asking where they could buy P4X333 boards, and no one had an answer. The P4X333 was AWOL.

Now, the P4X400 has apparently launched—this time for real. Shuttle and Soltek boards are rumored to be hitting the channel, and some publications received VIA-branded P4X400 boards (not reference boards, but full-blown products) to review. Unfortunately, we weren’t one of those publications, so we aren’t able to include the P4X400 here today. P4X333 test results appear below as an interesting little curiosity. We should have a P4X400 board soon, and we’ll review it then.

The method to our madness
We tested with a lot of different configurations for this review, so hold on. You’re about to see a lot of info here, and the table below will be important to understanding the results. For instance, we tested the Intel 845G chipset in three configurations: with DDR266 memory, with DDR266 memory using the 845G’s built-in graphics, and with DDR333 memory. (Although the 845G doesn’t officially support DDR333, the chipset is entirely capable of running the memory at DDR333 speeds, unlike the 845E.)

That said, I wish we’d had time to include a few other configurations. For instance, take the Intel 845E. Simple time constraints prevented us from testing with the 845E and including results. For what it’s worth, the 845G results should be very, very similar to what you’d get out of an 845E.

Also, please keep in mind that chipsets, when they’re put together well, shouldn’t affect overall system performance too drastically, all other things being equal. The key to better performance in current chipsets is usually the memory controller; chipset makers tend to optimize their memory controllers over time to squeeze out more performance. Support for faster memory types like DDR400 and PC1066 RDRAM will really make a difference, too. The performance results you’re about to see may not show the kind of eye-opening mega-differences you’d expect out of a new CPU or graphics chip. That’s expected with chipsets.

As ever, we did our best to deliver clean benchmark numbers. Tests were run at least twice, and the results were averaged.

Our test systems were configured like so:

Athlon XP Intel 845 Intel 845G Intel 850 Intel 850E SiS 648 VIA P4X333
Processor AMD Athlon XP 2200+ 1.73GHz Intel Pentium 4 2.4GHz Intel Pentium 4 2.4GHz Intel Pentium 4 2.4GHz Intel Pentium 4 2.4GHz Intel Pentium 4 2.4GHz Intel Pentium 4 2.4GHz
Front-side bus 266MHz (133MHz double-pumped) 400MHz (100MHz quad-pumped) 533MHz (133MHz quad-pumped) 400MHz (100MHz quad-pumped) 533MHz (133MHz quad-pumped) 533MHz (133MHz quad-pumped) 533MHz (133MHz quad-pumped)
Motherboard Shuttle AK35GT2/R Abit BD7-RAID Abit BG7 Intel D850MD Asus P4T533-C SiS 648 reference P4X333 reference
Chipset VIA KT333 Intel 845 Intel 845G Intel 850 Intel 850E SiS 648 VIA P4X333
North bridge VT8367 82845 MCH 82845G MCH 82850 MCH 82850E MCH SiS 648 VT8754
South bridge VT8233A 82801BA ICH2 82801DB ICH4 82801BA ICH2 82801BA ICH2 SiS 963 VT8235
Chipset drivers VIA 4-in-1
Intel Application Accelerator 6.22 Intel Application Accelerator 6.22 Intel Application Accelerator 6.22 Intel Application Accelerator 6.22 AGP 1.10.03
IDE 1.01.13
INF update 1.50 beta
AGP 4.11 beta
IDE filter driver 1.20a
Memory size 512MB (2 DIMMs) 512MB (2 DIMMs) 512MB (2 DIMMs) 512MB (4 RIMMs) 512MB (4 RIMMs) 512MB (1 DIMM) 512MB (2 DIMMs)
Memory type Corsair XMS3000 PC2700 DDR SDRAM Corsair XMS2400 PC2100 DDR SDRAM Corsair XMS2400 PC2100 DDR SDRAM

Corsair XMS3000 PC2700 DDR SDRAM

Samsung PC800 RDRAM Samsung PC800 RDRAM

Samsung PC800 RDRAM at 1066MHz

Corsair XMS3000 PC2700 DDR SDRAM

Corsair XMS3200 DDR400 SDRAM

Corsair XMS3000 PC2700 DDR SDRAM
Graphics NVIDIA GeForce4 Ti 4600 128MB (Detonator XP 28.32 video drivers)
Sound Creative SoundBlaster Live!
Storage Maxtor DiamondMax Plus D740X 7200RPM ATA/100 hard drive
OS Microsoft Windows XP Professional
OS updates None

Thanks to Corsair for providing us with memory for our testing. This memory is undoubtedly some of the best stuff on the market. Their XMS3000 DIMMs were actually able to overclock and run stable at DDR400 with conservative memory timings, and the new XMS3200 memory was able to run at 400MHz using moderate timings (though still at CAS latency 2.5, of course).

I should note that we’re using the Intel Application Accelerator drivers instead of the older Ultra ATA drivers. We elected to go this route because Intel is replacing its Ultra ATA drivers with IAA. In addition to providing support for Ultra ATA modes, the Application Accelerator does some prefetching to improve I/O throughput, so products based on Intel chipsets may have a slight advantage as a result. But then, that’s the point. We’re hopeful other chipset manufacturers will incorporate similar performance-boosting measures in their drivers, as well—if they haven’t already.

The test systems’ Windows desktops were set at 1024×768 in 32-bit color at an 85Hz screen refresh rate. Vertical refresh sync (vsync) was disabled for all tests.

We used the following versions of our test applications:

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
One of the key determinants of chipset performance is the memory controller in the north bridge chip. Sandra’s bandwidth tests measure one of the key elements for memory performance.

Paired with DDR400, the SiS 648 screams ahead of other DDR solutions and even outruns the 850E chipset with PC800 RDRAM. Only PC1066 RDRAM is faster. Of course, we’re only measuring one aspect of memory performance here. (I’m currently pondering a new memory latency test.) Our real-world tests will stress the chipsets’ memory controllers in different ways.

Business Winstone

The SiS 648 shows up very strong in Business Winstone, bested only by the PC1066 RDRAM solution and Intel’s 845G chipset, which has always done especially well in this test. Interestingly enough, the gap between the top and bottom spots here is over 10 points. Content Creation Winstone

Yet again, the 648 is near the top, both with and without DDR400 memory. LAME MP3 encoding

Obviously, chipsets don’t make a great deal of difference during MP3 encoding.

Codecreatures Benchmark Pro

With the super-intensive Codecreatures benchmark, we measure differences in tenths of a frame per second. The SiS 648 with DDR400 matches the 850E/PC1066 RDRAM combination stride for stride. 3DMark 2001 SE

We see a little more separation between the contenders in 3DMark. The 648 with DDR400 comes in just behind the 850E/PC1066 combo yet again. With DDR333, though, the 648 falls behind both the 845G and the P4X333. Serious Sam SE

The 648 puts in another strong showing in Serious Sam SE. Comanche 4

The SiS 648 takes spots two and three here, just behind the perennial leader. Obviously, the 648 has what it takes to handle 3D gaming and graphics well. We’ve seen reservations expressed over SiS AGP implementations in the past, but this latest one seems to work very well.

Speech recognition
Here’s a great chipset test: Sphinx speech recognition. Sphinx’s high-quality speech recognition algorithm is performance limited by memory bandwidth, but recent Pentium 4 chipsets have been managing to run Sphinx at speeds faster than real time. The true goal here is to process speech at about 0.8 times real time, so there’s sufficient CPU time available for the other overhead associated with speech-enabled applications. So far, none of our test systems has ever reached the 0.8 goal.

Our PC1066 test rig hits the 0.8 mark, and the 648 with DR400 is right behind it! Impressive stuff. The 648 isn’t quite as quick with DDR333 memory, performing just a tick slower than an Intel 845G chipset with DDR333. ScienceMark

Oddly, the 648 actually scores lower with DDR400 here instead of DDR333. Of course, we’re only talking about a hundredth of a point, so we can probably chalk it up to the test’s margin of error. Overall, the 648 is the strongest of the DDR-based Pentium 4 chipsets. Only the 850E with RDRAM is faster, and even then, not by much.

The Primordia test, which is just one component of the overall ScienceMark score, stresses memory pretty intensively, so we’re looking at its results separately. As you can see, the 648 is near the top of the pack yet again.

In the 648 chipset, SiS has delivered one of the best Pentium 4 chipsets available. Paired up with DDR400 memory, the 648 is faster than anything we’ve tested except the 850E chipset with PC1066 RDRAM. With DDR333 memory, the 648 isn’t always fastest, but it’s often close. Not only that, but the 648 showed no significant weaknesses in any of our tests, which is an especially important consideration in third-party Pentium 4 chipsets. (The stillborn VIA P4X333, for what it’s worth, was inexplicably slow in both Winstone tests.)

Beyond raw performance, the 648 comes with more of the latest features than any of its competitors, including AGP 8X, USB 2.0, Firewire, six-channel audio, a 1GB/s chipset interconnect, and ATA/133. Competing solutions from Intel offer much less: no official support for DDR memory over 266MHz, no ATA/133 support, AGP 4X, and a 266MB/s chipset interconnect. SiS 648 boards ought to be cheaper, faster, and offer more features than Intel DDR motherboards.

And unlike VIA’s P4X333/P4X400, the 648 should be widely available soon from top-tier manufacturers, with motherboard partners like Asus and Abit offering boards. In fact, the last SiS board I used extensively was Abit’s 645-based SD7-533, and it was nothing short of excellent in terms of stability, performance, and compatibility. Abit has already announced its successor, the SR7-8X.

I should note, also, that the 648’s performance with DDR400 memory is the first proof we’ve seen of DDR400’s viability. Naysayers have speculated that DDR400 wouldn’t offer much of a performance increase over DDR333 because of the latency penalties exacted by the slower memory timings required to make 400MHz DDR stable. Not so. In bandwidth-sensitive apps, DDR400 is quite a bit faster than DDR333. And it’s as fast as or faster than DDR333 even in what we’ve traditionally considered latency-sensitive apps, like Business Winstone. Our PC1066 RDRAM rig did put on quite a show today, but it had the ring of a swan song. DDR400 can take us to the next level of performance, and that’s probably good enough.

Chipsets like the SiS 648 will help. The 648 is excellent. I wouldn’t hesitate to put one of these into my own system, given SiS’s solid track record with the 640 series of P4 chipsets. And having said that, there’s really nothing more to say.

Comments closed
    • JustAnEngineer
    • 18 years ago

    [quote]Overclocking is so 5 years ago.[/quote]
    That is almost as long as it has been since Intel last offered a cost competitive CPU that overclocked easily. Running a Northwood “A” on a 133/533MHz bus like the SIS 648 supports looks like [b]free[/b] MHz from our good friends at Intel. You get to push the most expensive part of the system to higher performance while keeping your PCI and AGP buses at the correct speeds.

    Of course, my overclocked T-Bird-750 at 902 MHz and Duron-750 at 933MHz from a year and a half ago have been replaced by an AthlonXP 1700+ and a 1800+ at stock speed, so maybe you are right that overclocking is pass

    • MadManOriginal
    • 18 years ago

    Yay SiS! I love my SiS 645 board-no issues whatsoever.

    Have built a few systems for others based on the SiS 745. Again, solid and reliable.

    As long as SiS can keep offering similar performance for lower price than Intel, I see a bright future for them in the chipset market. The only thing that bugs me is on most current SiS boards (or at least when I was buying 6 months ago) for Intel CPUs are ‘stripper’ versions with none of the options for lots of additional on-board stuff (like RAID, firewire, etc.) Looks like that may be changing now though.

    • R2P2
    • 18 years ago

    So is [i]so[/i]. Heh.

    • Alanzilla
    • 18 years ago

    Overclocking is i[

    • Anonymous
    • 18 years ago

    1) I sure hate when newer articles/reviews appear below older ones on this site.

    2) Yeah, those AMDs are great. You know you’ve overclocked it too far when you can smell it and your fire alarm goes off. Plus, you can save money by turning off your heater in the winter. Of course, in summer there’s a problem, but hey, can’t have everything! 😉

    3) I admit it, I’m probably going to buy a -hammer…

    • TheCollective
    • 18 years ago


    • Anonymous
    • 18 years ago

    I just wish I could disable it all so I could be sure what speed I’m really running at…
    That’s why I buy AMD.

    • Forge
    • 18 years ago

    JustAnEngineer – Too bad it’s not that simple. Most CPUs past 1.6A require a voltage hike, and models past 2.0A often can’t pull off the 533 trick at all.

    OCing is nice, but I worry that P4 OCs aren’t worth the same as older CPU OCs. My P4 1.8A@2.7G wasn’t much faster than at 2.4G, though I’ll admit both were faster than the stock 1.8A speed. Throttling is also a concern… How much of that OC do you actually get, and how much is throttled away? Hot spot throttling can occur at higher speeds/voltages without bringing overall CPU temp up enough to trip the system-wide throttling. I just wish I could disable it all so I could be sure what speed I’m really running at, or maybe an Intel driver that logs throttles, declocks, and CPU errors…

    • JustAnEngineer
    • 18 years ago

    [quote]Now if P4s can reach price parity with Athlons I would be back in Intel’s fold.[/quote]

    Take one Northwood “A” Pentium4 (512K cache, 400MHz FSB, e.g.: Pentirum4 2.0A GHz). Take the motherboard reviewed in this article. Add some good DDR SDRAM and a top-notch heatsink like the Alpha PAL-8942, Swiftech MCX-4000, Thermalright SLK-478, etc.
    Set the motherboard for 533MHz FSB as you would for a Northwood “B” CPU. Voila! You’ve just installed the first cost-competitive Intel CPU to appear in years!

    • Anonymous
    • 18 years ago

    I have an MSI 745 Ultra and I’m quite happy with it, especially for the price. No strange (Via?) behavior or pitiful FSB overclocking – unlike my Shuttle AK35GTR (why’d they “let” you go so high on the bus when you aint getting more than 155?), it runs stable to 180mHz FSB and beyond, on fast timings.
    Maybe I’m an FSB whore, but I can encode to XVID (in ogg package) faster than YOU can!

    • TheCollective
    • 18 years ago

    —k: If you overclock all this can be yours AND much more. 😉

    • Anonymous
    • 18 years ago


    • Anonymous
    • 18 years ago

    Freon, I will say just this

    \m/ SiS 735 \m/

    • Steel
    • 18 years ago

    [q]Hey what is this ACR? I’m a little lost as to what the advantages of it over PCI are.[/q]The ACR slot is just a connection to the south bridge so you can use the sound, modem or ethernet features of the chipset. It’s mainly for OEMs to add a modem or ethernet connection at minimal cost. The same goes for AMR and CNR slots. (Didn’t this question get asked last time?)

    SiS has sure come a long way from the days of old. I never imagined they could ever give Intel chipsets a run for their money in either performance or reliability.

    • TheCollective
    • 18 years ago

    SiS absolutely rocks. I have been using a SiS645 based board for some time now and have to say it is as rock solid as any other chipset out there including Intel’s. I don’t know where they came back from but I sure hope they stick to it. They very well could become a serious competitor for VIA.

    • Anonymous
    • 18 years ago

    Almost the same as the nForce2 previewed last week. A bit faster, a few new features but no Serial ATA. I’ll wait for the next big step.

    • Caligula
    • 18 years ago

    #3, I’m pretty sure Asus is releasing a dual channel ddr mobo in either august or september. There was some press about it at hardocp and a few other sites a few weeks back….and it is fast!

    • sativa
    • 18 years ago

    [quote]Yes, our skin is pasty white, and sunlight hurts our eyes.[/quote]I think i’m going to puke, but instead i’ll say:

    The night time is the right time,
    The night time is the right time,
    Ahhhhh the Sun burns the Beast’s eyes.

    • JustAnEngineer
    • 18 years ago

    I still believe that the SIS 655 and/or VIA P4X600 chipsets with dual-channel PC2100 (266 DDR) are just what the Northwood “B” Pentium 4 needs to really shine. Any word on when these (or Intel’s version) will reach the market?

    • Rousterfar
    • 18 years ago

    Hey what is this ACR? I’m a little lost as to what the advantages of it over PCI are.

    • Freon
    • 18 years ago

    I’m tending to like SiS lately. I own an ECS K7S6A which I quite like, especially for the price. I also know several people with K7S5A boards, all of which are running well.

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