According to the manual the board has 4MiB of onbaord RAM, so you have to install two 8MiB and two 4MiB for totall of 28MiB of RAM. For the VRAM, it seems that the board has its own proprietary connector for expansion.

https://theretroweb.com/motherboards/s/compaq … v-3-p-n-00#docs

The video upgrade and cache module are very proprietary, the video upgrade has 1Mb vram on a flat card. Current Vram shows 4 - 256k x 8 for 1Mb.
Cache consisting of an Intel 82485 cache controller plus 64k of L2 cache also on a flat card like this:.
https://www.amibay.com/threads/compaq-23052-a … o-4-66i.106879/

cache is unobtanium
Vram upgrade is pointless, what even is the VGA chip on this board? looks like something Compaq cooked themselves and got manufactured by LSI? Is it VLB? is it half decent?
4/66 means the only CPU upgrade possible is with Overdrive or one of those Socket 1/2/3 Voltage Interposer Tweaker (Alpha)

Hmm going thru wayback machine think that could be a remarked Qvision, my guess a Qvision 1024 per the doc at TRW.
The 4/33i and 4/66i share all the same files and this be the video driver:
http://web.archive.org/web/20040731174129/htt … ocate/3_51.html
http://web.archive.org/web/20040701081037/htt … nload/1051.html
Wasn't the Qvision used on Compaqs EISA video cards ???

Yes QVision (the Motorola chip rather than LSI)...@Robert B showed the VRAM upgrade module a year or two back

Ah, so the vram is difficult to get, that’s fine. And It is a Qvision 1024, you’re correct.

As for the memory, the board has 4mb of onboard ram? The bios says there’s 4mb of ram, but there’s a card in bank A of the memory module slot. Is that correct?

Back again with another question, rasz_pl said “4/66 means the only CPU upgrade possible is with Overdrive or one of those Socket 1/2/3 Voltage Interposer Tweaker (Alpha)”. Is that it for cpus? I can’t find much on the board, but what about interposers or something? Any possibilities of 133mhz?

Pentium overdrive will require one of those Voltage Interposers blocking 5V from motherboard and feeding CPU its own 3.3V

Gotcha. I’d need to buy one of those first if I wanted a 5x86. For the Pentium overdrive, I though they had the power regulator built in?

The MMX overdrives do, but those are for socket 5

Ok, so the MMX overdrives are specifically for Pentium computers and not compatible with the 486. With that being said, I got this information from the Wikipedia page, and the wording confuses me on whether it’s 5 or 3.3

Yes, Vramis unobtanium. Is lijkt to have one for my Deskpro XE 4/66.

Yes, the cache module gives you quite some extra performance. I'm lucky enough mine has the module but I haven't seen another one around.

I've put in 4x 16MB ram and it still didn't go over 32MB available. As with 2 modules. With 1 module it went straight to 20MB total. Also note the onboard 4MB ram is 70ns so putting in 60ns ram won't make it faster.

In all it's a nice 486 system. It's fast enough with the L2 cache and the video chip is better than average imo.
The windows bios is stored on the hard drive, in a separate partition, so that's something to keep in mind.

Oh befor I forget to mention: the latest bios supports the pod CPU.

Thanks! Would you happen to have information about finding the latest bios?

Didn't realize the vram upgrade was that uncommon. Guess I got lucky with the Pentium Prolinea I picked up as its got one.

Anonymoose wrote on 2024-06-18, 00:23:

Thanks! Would you happen to have information about finding the latest bios?

Systems shipped with a number of different board / ROM revisions - which is yours (should be on a labelled chip next to the Dallas RTC)