An update on AMD 790FX motherboards

We weren’t particularly impressed with AMD’s 790FX chipset when we took our first look at it last month. The Gigabyte GA-MA790FX-DQ6 motherboard we tested had numerous issues, including BIOS quirks and relatively high power consumption. The chipset itself appeared flawed, as well, exhibiting slow USB and PCI performance and compatibility problems between Windows Vista and Serial ATA drives running in AHCI mode.

To gather a broader impression of the 790FX, we’ve rounded up new motherboards based on the chipset from Asus and MSI to see how they compare with Gigabyte’s initial offering. We’ve also dug deeper into the SB600’s support for AHCI in Vista, discovering some troubling performance characteristics along the way. Keep reading for a quick look at the current 790FX motherboard landscape.

New boards from Asus and MSI

With a street price hovering around $265, Gigabyte’s GA-MA790FX-DQ6 comes in at the very high end of the 790FX motherboard spectrum. There, it’s joined by Asus’ M3A32-MVP Deluxe WiFi-AP Edition, which can be had for about $35 less. At the other end of the map we find MSI’s K9A2 Platinum selling for as little as $156—clearly the bargain of the three. Time constraints prevent us from giving these boards a full work-up. We’ve run them through our full chipset test suite, though, and have a complete set of results to report.

Asus’ M3A32-MVP Deluxe WiFi-AP Edition

These boards are pretty much what you’d expect from their respective manufacturers. The Asus is packed to the gills with onboard peripherals, including an 802.11g Wi-Fi module. Asus manages to squeeze four PCIe x16 slots onto the board while ensuring that monster graphics cards won’t obscure access to onboard ports, as well.

Asus bundles an intricate memory cooler in the box

Adding to the recent trend toward elaborate chipset coolers, Asus bundles a memory cooling module with the board that links memory modules to the chipset heatpipe network. This adjustable memory heatsink is designed to be used in lieu of traditional DIMM heat spreaders, but it only works with two modules at a time.

MSI’s K9A2 Platinum motherboard

As one might expect, the MSI board is quite a bit more subdued, lacking Wi-Fi and fancy memory cooling. MSI still manages to squeeze in four PCIe x16 slots, though, and they’re spaced to allow for four double-wide graphics cards. However, longer double-wide cards installed in the second PCIe x16 slot will obscure acess to some, if not all, of the board’s SATA ports. Note that the K9A2 Platinum locates the north bridge chip slightly to the left of the CPU socket rather than directly below it.

Specifications compared

To allow for quick comparison, we’ve summarized the specifications of the M3A32-MVP Deluxe and K9A2 Platinum below.


Asus M3A32-MVP
Deluxe WiFi-AP Edition

MSI K9A2 Platinum

CPU support
Socket AM2/AM2+
Phenom, Athlon X2 processors
Socket AM2/AM2+
Phenom, Athlon X2 processors

North bridge
AMD 790FX AMD 790FX

South bridge
AMD SB600 AMD SB600

Interconnect
PCIe x4 (2GB/s) PCIe x4 (2GB/s)

Expansion slots
4 PCI Express x16

2 32-bit/33MHz PCI

4 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 8GB of DDR2-667/800/1066 SDRAM


Storage I/O
Floppy disk

1 channel ATA/133

4 channels Serial ATA with RAID 0, 1, 10 support

2 channels Serial ATA with RAID 0, 1 support via Marvell 6121

Floppy disk

1 channel ATA/133

4 channels Serial ATA with RAID 0, 1, 10 support

2 channels Serial ATA with RAID 0, 1 support via Promise T3

Audio 8-channel HD audio
via SB600 and Analog Devices AD1988B codec
8-channel HD audio
via SB600 and Realtek ALC888 codec
Ports 1 PS/2 keyboard

6 USB
2.0 with headers for 4 more

1 RJ45 10/100/1000 via Marvell 88E8056

1 802.11g Wi-Fi via AzureWave AW-NA830

1 1394a Firewire via Agere L-FW3227 with header for 1 more

1 eSATA via Marvell 6121


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 digital TOS-Link S/PDIF output

1 PS/2 keyboard

1 PS/2 mouse

4 USB
2.0 with headers for 6 more

1 RJ45 10/100/1000 via Realtek RTL8111B
1 1394a Firewire via
VIA VT6308P with header for 1 more

2 eSATA via Promise T3


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

Given the price difference between the boards, the MSI’s specs certainly look promising. About the only integrated peripheral it lacks is Wi-Fi, and it even manages one more expansion slot than the M3A32-MVP. The boards use different chips to provide auxiliary storage, Firewire, and Gigabit Ethernet, though. As you’ll see in a moment, there are clear differences in peripheral performance between them.

Neither the Asus nor the MSI board exhibited any BIOS irregularities during testing. The M3A32-MVP does provide a slightly more extensive array of overclocking options, though.


Asus M3A32-MVP
Deluxe WiFi-AP Edition

MSI K9A2 Platinum

Bus speeds
HT: 200-600MHz in
1MHz increments

DRAM: 400, 533, 667, 800MHz

PCIe: 100-150MHz in 1MHz increments
HT link: 200, 400, 600, 800, 1000MHz

HT: 200-600MHz in
1MHz increments

PCIe: 100-150MHz in 1MHz increments
HT link: 200, 400, 600, 800, 1000MHz


Bus multipliers
CPU: 5x-13x in 1x increments (Athlon X2 5200+) CPU: 5x-13x in
0.5x increments (Athlon X2 5200+)
HT link: 1x-13x in 1x increments

Bus dividers
NA HT:DRAM: 1:1,
1:1.22, 1:1.66, 1:2
Voltages CPU: 0.8-1.6875V in
0.0125V increments

DRAM: 1.8-2.5V in 0.02V increments

PCIe: 1.1-1.4V in 0.02V increments

NB PCIe: 1.8-2.1V in 0.1V increments

SB: 1.2-1.4V in 0.02V increments

HT: 1.2-1.5V in 0.1V increments
CPU NB: 0.8-1.6875 in 0.0125V increments

CPU: 1.318-1.587V in
0.038V increments

DRAM: 1.8-3.1V in 0.05V increments

NB: 1.125-1.525V in 0.025V increments
HT: 1.125-1.525V in 0.025V increments


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

Fan speed control
CPU CPU

The Asus BIOS’s advantage comes in the voltage department, where it provides access to a much greater range of CPU overvolting options. It’s also possible to tweak a greater number of M3A32-MVP voltage variables. However, the K9A2 is better equipped for memory overclocking thanks to its higher memory voltage ceiling. MSI’s processor fan speed control is a little better than what you get with the Asus board, too, thanks to the ability to set a temperature target and fan speed percentage arbitrarily.

Benchmark results

We used an identical test configuration to that of our 790FX chipset review. The latest BIOS revisions were used for the Asus and MSI boards—revision 0603 and 1.1, respectively. As you’ll see, performance doesn’t vary much from board to board until you get into peripheral testing. We’ll save our commentary for the conclusions.

Memory performance

STARS Euler3d computational fluid dynamics

Worldbench

Gaming

Serial ATA performance

USB performance

Firewire performance

Ethernet performance

PCI Express performance

PCI performance

Power consumption

Overclocking

340MHz on the M3A32-MVP

In testing, we were able to get the M3A32-MVP Deluxe stable with a 340MHz HT clock before the system refused to post.

330MHz on the K9A2 Platinum

The K9A2 Platinum fared nearly as well, sailing up to a 330MHz HT clock before flaking out. In both cases, the boards achieved their highest HT clocks with stock voltages. Additional juice didn’t help them scale any higher.

AHCI issues

A documented compatibility problem between Windows Vista and the 790FX chipset’s SB600 south bridge component currently complicates running drives in AHCI mode. As Microsoft notes:

When you try to install Windows Vista on a portable computer that uses an ATI SB600 Series chipset, each driver may take a long time to install. Therefore, the Windows Vista installation process may take several hours.

That’s if it works at all. One can install Vista by putting the SATA controller into IDE mode, but AHCI mode is necessary to take advantage of Native Command Queuing and SATA device hot-swapping, so it’s not a trivial capability to lose.

With a hotfix from Microsoft, we were able to get drives running in AHCI mode on both boards. However, doing so quickly all but requires an auxiliary storage controller. Vista must be installed with the south bridge running in IDE mode. You then have to move the hard drive to a secondary controller, switch the south bridge to AHCI mode, and apply the hotfix and necessary drivers before swapping the drive back. This problem should be resolved by Vista Service Pack 1, but without slipstreaming, that won’t necessarily make the installation process any easier.

The 790FX chipset’s AHCI problems don’t end with installation, though. There are also some performance oddities that we can illustrate nicely with IOMeter. In the results below, the 790FX is shown with the SB600 running in IDE mode, in AHCI mode with Windows Vista’s drivers, and in AHCI mode with 2.5.1540.47 drivers provided by AMD. Incidentally, those drivers come from Silicon Image, which is apparently responsible for the SB600’s Serial ATA controller.

With AMD’s official drivers, performance doesn’t scale at all as the load increases—even IDE mode offers higher transaction rates. Windows Vista’s native drivers seem to have it right; SB600 performance ramps more aggressively than even the nForce 590 SLI.

AMD’s official drivers also deliver much slower response times, suggesting that Vista’s native drivers may be the way to go.

Except for one little problem: CPU utilization. Vista’s native drivers may offer the AHCI performance we’re used to seeing, but they exact a huge CPU utilization penalty in the process. Silicon Image’s AMD’s drivers offer competitive CPU utilization, at least, but we’ve already seen that their performance is lacking.

At the moment, running the SB600 in AHCI mode requires choosing between poor performance or high CPU utilization. Neither is acceptable in our opinion, especially since competing chipsets seem to have no problems getting it right. Let’s hope AMD can address this issue with its upcoming SB700 south bridge.

Conclusions

After running the M3A32-MVP Deluxe and K9A2 Platinum through our gauntlet of chipset and motherboard tests, it appears our initial prognosis for the 790FX chipset was largely accurate. The Asus and MSI boards we’ve looked at today aren’t any faster in application tests than Gigabyte’s GA-MA790FX-DQ6, which puts them right in line with competing nForce 590 SLI boards. However, the SB600’s AHCI issues and slower USB performance remain. The SB600 appears to have some PCI performance quirks, as well, with the Gigabyte and MSI boards delivering much lower PCI throughput than our nForce 590 SLI platform. The Asus board fared a little better in our PCI throughput test.

Indeed, the M3A32-MVP had a performance edge over the K9A2 Platinum through much of our peripheral suite. The Asus board isn’t particularly exemplary on that front, but the MSI board suffers from a Gigabit Ethernet chip with atrocious CPU utilization and a Firewire controller that’s a little slow. To its credit, the K9A2 does deliver lower power consumption than the other 790FX boards. However, it only draws about 12 fewer watts than the nForce 590 SLI, which is a relatively modest advantage.

If you absolutely must buy a 790FX motherboard today, the Asus M3A32-MVP Deluxe and MSI K9A2 Platinum are better alternatives to the Gigabyte GA-MA790FX-DQ6. For those looking for a high-end board packed with fast peripherals, the Asus is the best option. Those looking to save a few dollars are much better off with the K9A2 Platinum.

That said, we still recommend waiting for the second wave of 790FX boards to hit with updated SB700 south bridge chips. By then, AMD should have B3-stepping Phenom chips available that correct the TLB erratum, as well.

Comments closed

Pin It on Pinterest

Share This

Share this post with your friends!