I'll dump the bios when I get a chance and poke around with my clumsy binary ready skills to see if I can spot anything.

douglar wrote on 2020-11-05, 21:49:

I'll dump the bios when I get a chance and poke around with my clumsy binary ready skills to see if I can spot anything.

OK, I feel more stupid than usual. Perhaps I truly have begun to enter my dotage.

Here's the deal. The other chip is not a rom at all.

I had it in my reader and got out my magnifier to read the small print. Just about rammed my glasses through my head with the resulting face palm.

The other chip is the ATI68830 RAMDAC.

So the reason for the double image is pretty freakin clear in hindsight. Double image because I had two ramdacs.

All I had to do was pull the ATI68830 and it was all good. Both the TLC34075 and the TLC34076 were compatible with the Mach32 card all along.

If anyone wants a spare TLC34075 for their mach32 card, let me know and I'll be happy to mail it away so there's fewer reminders of this incident in my life =)

Here's a link to the rom that I dumped--

https://www.dropbox.com/s/fv6m6uwondp5bd5/VLB … 0.1993.BIN?dl=0

I read this somewhere and was trying to find the link to where I'd seen it, but yeah the second dip socket was either labelled even BIOS or the original RAMDAC.

Glad you got it sorted!

That said, these kinds of debugging hijinks and occasionally eureka moments are why we do this right!?

I tested a VLB Mach32 EXM195a 2MB VRAM:

against a VLB Mach32 EXM229 2MB DRAM:

on a 486dx2-66 equipped Shuttle HOT 419 v1.0 mobo utilizing a Opti 82C894 chipset & 512kb cache.

I compared landmark scores--

• Mach32 EXM195a VRAM -- 7,740 char/ms - 7740 is the slowest VLB score that I've seen
• Mach32 EXM229 DRAM -- 10,922 char/ms - 40% faster

I also did the high quality doom benchmark on both cards.

• Mach32 EXM195a VRAM -- 2,869 realtics -- One of the best VLB scores
• Mach32 EXM229 DRAM -- 2,693 realtics -- The best VLB score I have seen on this system

Not sure why the landmark scores are so bad but the doom scores are so good.

Would something like UNIVBE 6.7 improve landmark scores?

Aren't the landmark graphics scores just based on text modes?
Since when was landmark a reliable measure of anything anyway?