Asus A7A266-E bios settings?

liftmusic · May 12, 2002

I was poking round the bios earlier and I came across two entries
in Advanced -> Chipset these are System Acceleration Mode
enabled/disabled currently disabled and also VideoMemoryMode
UC/USWC currently UC can anyone shed any light on what these do? System Accelration mode sounds kinda groovy! as always any help is appreciated.

Didou · May 13, 2002

The system acceleration mode in your mainboard is probably an option to enable certain aggressive settings for memory timings, etc...

Try enabling it seeing if your system is still stable. I have an ASUS A7V266-E & there's an option called Performance level ( Normal / Optimal ). If I select Optimal, RAM Timings are set to CAS2, etc...

If you start having random lock ups, I suggest setting it back to default.

Is there anything mentionned in your BIOS manual about it ? I don't have an A7A266 so i'm only guessing here.

As for the VideoMemoryMode, it's common to ASUS mainboards. I'm not sure if they're the only ones to have it. Could anyone confirm if they have this option with a non ASUS mainboard ?

Here's a little explanation I found on the subject.

Video Memory Cache Mode (ASUS mainboards)

By definition, video memory is excluded from being cacheable since otherwise the large data chunks would fill up the L2 chache of the CPU immediately. When the CPU calculates 3D, that is, floating point operations, every data point needs to be written to the local frame buffer (on board graphics memory). Unfortunately, the CPU can either write or calculate, therefore each write cycle interrupts the floating point operations, in simple terms, the FPU unit can only work at half speed. Intel were the first to incorporate 8, so called, write combine buffers on the Pentium II, which was one of the reasons why the PII had a superior 3D performance compared to the original K6, at least at low resolutions. The reason is simple, instead of single bit writes, the data are temporarily stored in write combine buffers and released in burst mode. Therefore, depending on the size of the WC-buffers, FPU calculations are interrupted much less frequently, in other words, the graphics performance of the CPU is almost doubled.

Graphics data inherently feature high locality, therefore there is no problem pipelining these data. With the CXT revision of the K6-2 and the K6-III, AMD added two write combine buffers and, as we were the first to post, proper addressing of these buffers via software would boost graphics performance by as much as 30% within the identical hardware configuration. The Athlon family has four aggressively programmed 64 bit WC buffers buffers that can be placed over the local frame buffers for both data and hardware acceleration. Compared to the PII / III WC buffers, the novelty is being capable of executing out of order writes in ascending and descending order and thus taking write combining to a new level. This way the efficacy of the 3D floating point operations can almost be doubled. Available settings in the ASUS A7V BIOS are either uncached (UC) or uncached speculative write combining (USWC). Needless to say that USWC needs to be supported by both graphics adapter hardware and drivers but if it works, it is one sweet feature.

from Lost Circuits

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Asus A7A266-E bios settings?

liftmusic Newcomer, in training

Didou Bowtie extraordinair!