That's a picture of the board. I got it off ebay for like $20 a couple months ago, and it has sit in a bag since. Mostly because of other projects. Tonight I found myself "getting around to it" and firing it up. It seems to run fine but has developed a few quirks. The most major of which is some sort of "gate a20" error i get loading dos. The dos boot disk I use basically loads a xms manager (dos 6.22 himem.sys), a cd driver, and cute mouse. Pretty basic. I think it would be best if I list what I did and in the order I did it. If for nothing else that retrace my steps.
drop in 4x 4mb simms, test with vlb video, boots
spend 2 hours finding jumper settings online LINK: http://stason.org/TULARC/pc/motherboards/U/UNIDENTIFIED-486-PANDA386V.html
install 256kb cache
benchmark*
remove processor and install amd386/40 (change appropriate jumpers)
10 minutes to find out vlb wont work with this processor and install tseng et4000, works
benchmark
revert to 486dlc and install cyrix 387 co-pro
benchmark
install 32mb ram
night goes to hell
revert to previous ram
standard troubleshooting
15 minutes of staring at the bios settings
realize its almost 4am and you might need help
* During my testing, I find out that the board automatically enables the L1 cache on the chip. However the default setting for the L2 is off. using the cyrix program to "turn the cache on" does nothing. IDE drive performance is WORSE than my "real" 386. in benchmarks it scores a 19 in speedsys and manages 21 fps in 3dbench. installing a cyrix math-co drops this to 9.9 and 18 respectfully. cache benchmarks show plateaus in the expected locations. 1kb,256kb
For the meat and potatoes of my evening, it seems when I installed 32mb of ram (8x4mb) it seems that everything hit the fan. I got no errors during post, but once himem was called I get this error; "Unable to control A20 Line". speedsys wont do its memory benchmarks however everything else seems fine. after several hours on teh internets, I'm no closer to a solution than before. One website says that the a20 line is the keyboard controller, but that doesnt make sense to me. This is a memory issue, and the keyboard works just fine.
please forgive me if I'm hard to understand, its now almost 4:30am, but I have 2 real issues. The most pressing issue is the himem a20 issue. This board was just fine the first few hours of the night, I dont know what happened or where, but some insight is welcome. The 2nd issue is moot unless I fix #1, but I'd like to know why the performance goes down the shitter when I put a cyrix math-co in this thing. I would think a cyrix core 486 and corresponding cyrix math-co would at the very least do no harm...
thanks in advance, time for bed.