I had a similar experience when I got my 386 repaired and running again for the first time with it being excruciatingly slow:
Enable Main BIOS Shadow and Video BIOS Shadow.

Copies the ROM areas into RAM. RAM is faster than ROM memory.

Agree ! enable shadowing should help a bit. Not sure what Norton SI used for its speed comparisons on 386....
The missing chips could be for ram buffers to cpu (and found not needed). The Opti 82c382 is the memory/cache controller and hard to follow traces but does not look like it is involved in the missing chips AFAICS.
As for "color" and "PIPE" not sure why they routed those to same location as front panel stuff, that is very odd for any old board.
added: have you tried with turbo jumpered to see if SI goes up ? If you do and SI increases, then try with turbo jumped and pipe unjumped...just some thoughts

Its really low end for 1991 to not have any cache. So is sparse 2 layer layout. This was low effort low cost product.
"missing" chips are most likely more 74f244 buffers simply deemed not needed.
There is only one mention on google about this board on some Korean local classifieds "VINTAGE INTEL 386 Motherboard 80386 DX - i386 DX 25MHz A325N-B. USD 30.00"
Chipset is marked/rated 25MHz and judging by this single mention it was originally shipped in a 25MHz system. Someone overclocked the board, but swapped CPU instead of trying to OC 25MHz version.

All in all Im sure it was enough for just released Wing Commander 😀

Thanks for the info everyone!

Horun wrote on 2024-09-15, 02:46:

Agree ! enable shadowing should help a bit. Not sure what Norton SI used for its speed comparisons on 386.... The missing chips […]
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Agree ! enable shadowing should help a bit. Not sure what Norton SI used for its speed comparisons on 386....
The missing chips could be for ram buffers to cpu (and found not needed). The Opti 82c382 is the memory/cache controller and hard to follow traces but does not look like it is involved in the missing chips AFAICS.
As for "color" and "PIPE" not sure why they routed those to same location as front panel stuff, that is very odd for any old board.
added: have you tried with turbo jumpered to see if SI goes up ? If you do and SI increases, then try with turbo jumped and pipe unjumped...just some thoughts

Right, so:

Tried a bunch of games, and they perform very well at what I expect of a DX33. The SIMMs are 70ns, so there is a little room for improvement here.
Is a 386 DX 33 with 8MB something that existed? My 386 back in the day was 2MB then upgraded to 4MB.. so 8MB feels like too much, no?

I would try clearing and resetting the BIOS.

The BIOS was cleared several times during my tests. By default, it initializes to very slow settings: No BIOS shadowing, 1-wait state for memory read/write, and of course time and date reset to 1980,1,1...

wbahnassi wrote on 2024-09-15, 22:07:

Is a 386 DX 33 with 8MB something that existed? My 386 back in the day was 2MB then upgraded to 4MB.. so 8MB feels like too much, no?

Sure. Back in the day we had a 386DX-33 on a motherboard with 12 30-pin SIMM slots. It started off with 4MB and was then steadily upgraded to 12MB. That extra RAM came in handy for multitasking OSes like OS/2 Warp 3.0 and, to a lesser extent, Windows 95. It had an ETEQ301 (82C491, 82C493) chipset and 64KB cache. It was 30+ years ago but ISTR that its Norton SI score was about where it expected it to be, maybe slightly slower like 35.8. No longer have that system so I can't re-run it.

>Is a 386 DX 33 with 8MB something that existed?

Probably not in 1992, but my first PC AMD 386DX40 started with 4MB and then got upgraded to 8MB after I got HDD. I think I kept it until Celeron 300A.

wbahnassi wrote on 2024-09-15, 22:07:

Thanks for the info everyone! […]
Show full quote

Thanks for the info everyone!

Right, so:

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Tried a bunch of games, and they perform very well at what I expect of a DX33. The SIMMs are 70ns, so there is a little room for improvement here.
Is a 386 DX 33 with 8MB something that existed? My 386 back in the day was 2MB then upgraded to 4MB.. so 8MB feels like too much, no?

Please play with TURSW and PIPE jumper.
Can you repost the benchmark screen in fastest configuration please?

The last image I posted is titled "Turbo ON, PIPE ON". That is the fastest configuration I got. It has the TURSW and PIPE both jumpered. The score is 29.4 in SI8.
The other images show the SI8 scores for the other combos of TURSW & PIPE. The slowest is both TURSW & PIPE unjumpered, and that gave 12.6 points, and SI8 classified the processor as a DX 17MHz.

wbahnassi wrote on 2024-09-17, 03:03:

The last image I posted is titled "Turbo ON, PIPE ON". That is the fastest configuration I got. It has the TURSW and PIPE both jumpered. The score is 29.4 in SI8.
The other images show the SI8 scores for the other combos of TURSW & PIPE. The slowest is both TURSW & PIPE unjumpered, and that gave 12.6 points, and SI8 classified the processor as a DX 17MHz.

Sorry.
A faster 386 benefits from cache.

I was trying to install Win3.11 and the installer was failing to launch the setup program after it's done copying the initial files. It was a memory problem. I had 0-wait states. Once set to 1, the setup program worked fine.

The sticks I have are 4 1MB sticks 70ns. Is it worth going for 60ns? Would that allow me to go back to 0-wait states or still not enough?