I keep repeating this to people trying to squeeze more performance out of their builds, if you are only interested in playing old games it's always easier and cheaper to just use something a little more powerful.

Assuming you actually enjoy and want to play with the hardware, the fast 386/40 you are seeing are a combination of chipset, memory/cache timing and a BIOS that allows detailed adjustments for both. So I'd start by checking if I can use lower WS for the RAM and cache. Hint: most 70ns modules don't play nicely with 0WS on a 40MHz bus, on some chipsets you can't even achieve 0 with 60ns sticks.

Once you're happy with the results of benchmarks that don't depend on the VGA you can then try different cards and bench graphics/games

konc wrote on 2021-07-19, 17:53:

I keep repeating this to people trying to squeeze more performance out of their builds, if you are only interested in playing old games it's always easier and cheaper to just use something a little more powerful.

Assuming you actually enjoy and want to play with the hardware, the fast 386/40 you are seeing are a combination of chipset, memory/cache timing and a BIOS that allows detailed adjustments for both. So I'd start by checking if I can use lower WS for the RAM and cache. Hint: most 70ns modules don't play nicely with 0WS on a 40MHz bus, on some chipsets you can't even achieve 0 with 60ns sticks.

I'm mostly just interested in seeing this specific computers maximum performance. I know I could just throw together a pentium or whatever but sometimes it's fun just to tinker around with the 386. I'll take another long search through the bios but it doesn't really allow for much fine tuning. I have another 386 mainboard that is extremely similar being as these two original computers were built around the same time so I'm tempted to see if the chipset or bios on that one is newer or older.

(I'm thinking older as that pc only had a 330mb drive and a cassette drive where the one I'm working with originally had a 880mb drive with an added isa card that from what I understands allows the bios to read more than 504MiB)

Either way this AMI bios is from 1990 and is extremely outdated, I barely got the sd to ide working being as there is no autodetect and I couldn't get it working until I found a cool "whatide" freeware developed way back that has little documentation. The SD to IDE doesn't work over 504MiB though, and if it does I can't seem to get it actually working.

Charleston wrote on 2021-07-19, 17:28:

Is it the chipset? This mainboard is a bit undocumented and doesn't seem very good. Don't remember what chipset it has exactly but I believe it's some sort of OPTI.
If I were to attempt to OC the 40mhz cpu to 50mhz with a 100mhz oscillator would that even work? I've heard of people doing it but I'm not sure if the dx-40 would reach unmanageable levels of heat. Maybe I'd need an active cooler at that point.

If you can figure out what chipset it is, some of those OPTis have datasheets, and there may be things you can punch into DEBUG even if the BIOS doesn't let you access or change them.