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Reviewed by: Carl Nelson [04.14.08]
Manufactured by: Universal Abit


SATA Performance

It all started when I first booted up the AX78 to begin testing. As always, I set up the BIOS for optimal performance. Some default settings need to be changed, such as memory timings, and drive controller settings. As always, I set the drive controller to use AHCI. This essentially allows SATA drives to perform to their fullest; for instance, you usually can't have NCQ without it, and it also allows hot-plugging. Vista natively supports AHCI, so there is no need for drivers at the beginning of installation.

Big mistake.

It's actually a documented issue with Microsoft. If you attempt to install Vista on a drive using the SB600's AHCI, the installation will simply hang, and eventually freeze or even BSOD.

There is a hotfix (which of course is integrated into SP2), but of course, you can't install a hotfix until the OS is installed.

The workaround is to set the drive controller to IDE mode, which is usually not the optimal setting to use for performance, and install Windows that way. After that, you can install the hotfix (or SP2), and can then enable AHCI.

However, to install the AHCI drivers (either Microsoft's integrated drivers, or those supplied by ATI) you will need to have the drive controller set to AHCI mode. But once Windows is installed, you can't simply switch it over to AHCI mode and boot; there are no drivers!

The solution to this is to move the system drive over to an external controller. However, the AX78 doesn't have an integrated auxilliary controller, so you'll need to install your own. I'm not too sure if many people have these laying around. Luckily, I have an ExpressCard SATA controller here for review, and a PCI-E > ExpressCard adapter. So I was able to install that, move the drive over to it, reboot Windows, set the board to use AHCI, reboot again, install the drivers, shut down again, switch the drive back to the motherboard's controller, and boot up. Finally! AHCI mode!

As I mentioned, AHCI should be the best mode for SATA drives. Should be, if your drive controller works properly. Unfortunately, the SB600 just doesn't work properly. You actually have 2 choices of drivers to use; Microsoft's SP2 drivers, or ATI's drivers from last year. We tested both of those.

To see how NCQ performs, I also tested the drive using IOMeter. IOMeter is a hard drive subsystem benchmark that recreates a high-user environment. In other words, it's more like running the drive in a workstation or database server than a desktop system. But the performance difference will be more profound.

I also ran the standard HDTach benchmarks, to test pure data transfer throughput.

The tests were run in Native IDE mode, AHCI Mode with SP2 drivers, and AHCI Mode with ATI's drivers. The NForce 4 570 Ultra board was tested using its standard non-RAID mode (it doesn't support AHCI, but somehow they support NCQ through the NF4 southbridge).

As you can see, enabling AHCI yields mixed results in the IOMeter Database test. With the integrated SP2 drivers, the drive seems to perform exactly as it should; right in line with the NF4 controller. However, with the ATI drivers installed, performance is no better than straight IDE mode. In fact, it's even worse!

Looking at CPU performance, we see that the SP2 drivers, while the fastest solution, uses way too many CPU cycles to achieve its performance. The other modes are all in line with expectations; about 1-2% and no more.

HDTach paints another picture, but it's also an ugly one. The SP2 AHCI drivers suffer in pure data transfer rate, and are also hit by the same nasty CPU usage issue. The margin of error on HDTach is a rather high +/- 2%, but there is no other way of looking at this 17% result. The AHCI controller is essentially broken on the SB600, and should not be used. For optimal performance, I think IDE mode is the best choice.

Next Page: (Overclocking; Conclusion)