First post, by GigAHerZ
I've been playing around with my M321 motherboard (has 386DX40 cpu, cyrix fpu, 256KB of cache with write-back cache chip included, etc) and i have been comparing it to few other boards in terms of bios options.
This board (M321) unfortunately don't have AT Clock divider option. I suspect it's by default 6, therefore ISA bus is running at 6,66MHz.
I would like to set the divider somehow.
I've played around with AMISETUP program, that can modify some hidden options, that are not present in boards bios. I've been able to set slow-refresh and gained a miniscule amout of additional memory speed.
While it doesn't show any AT bus divider options, it does have an ability to set custom registers completely manually.
Now, based on that, i would like to find that board's chipset's datasheet. By playing around with upper memory tools, often this board is seen to have Opti 82c495 chipset. I have that datasheet, but it doesn't seem to correlate with my current settings in registers. The register addresses seem to be off, while the content seems to somewhat match. I searched for the register on my board that would correlate with similar settings in the 82c495 datasheet's register 25h content. (Contains AT divider bits) If i remember correctly, my address was 65h. But setting the last 2 bits to different values didn't have any effect on any benchmarks. (Yet, it should, as tested on different board which has this AT divider options in bios)
Based on all of that, i would like to know or somehow get the datasheet for the M321 chipset. It has PC Chips CHIP5 and PC Chips CHIP6 chips as the main chips.
Any suggestions are welcome.
"640K ought to be enough for anybody." - And i intend to get every last bit out of it even after loading every damn driver!