flakes wrote on 2026-05-15, 23:03:

Has anyone tried this in the Presario 7x / 9x machines..... I just got 720 and thinking of buying /building 1 of these....

https://theretroweb.com/motherboards/s/compaq … -900-series-486 is directly linked in https://github.com/wichers/Compaq-Cache-Module-197005-001 so yes

flakes wrote on 2026-05-15, 23:03:

Only issue is I only need 1 not 5 or 10 when you do a PCB way order.....

does it matter how many you order if total is still like $5?

xkad9 wrote on 2026-06-08, 13:33:

I think I'll give this a shot but in your github it's missing a BOM for the components? (unless I'm completely blind - also a possibility)

good catch, neither does mine https://github.com/raszpl/FIC-486-GAC-2-Cache-Module 😐
you have to download Kicad, load the project, select diagram, and then view BOM

xkad9 wrote on 2026-06-08, 13:33:

I'm a complete idiot when it comes to electronics - but I can solder. I just upload the gerbers.zip file to PCBWay and order the boards that way, right?

afaik jlcpcb comes out cheaper, might depend on shipping, but in general yes

I’ve ordered a few PCBs from JLCPCB using the 2024 Gerber files from the GitHub repo (https://github.com/wichers/Compaq-Cache-Modul … ain/gerbers.zip)...

For this 2024 version of the board, can anyone confirm that 8 × IS61C256AH-12J (SOJ-28) 32K×8 SRAMs are valid drop-in parts?

Also, what is the correct resistor configuration for a board populated with 8 × 32K chips (no 64K parts)? Is it simply 2 x 10k on 2-3?

*** EDIT: Sorry, that was not a smart question as the board is clearly for SOJ-32 chips...

Madao wrote on 2026-01-15, 07:47:

i have build cache for my compaq prolinea 4/66. […]
Show full quote

i have build cache for my compaq prolinea 4/66.

I placed CY7C199-20 on him (20ns 32kb SRAM ) and 256kb L2 Cache works.

Placing of 62256 on 1MBit-SRAM footprint: Pin 1 of 62256 should fit to Pin 3 of 1MBit Footprint. And DIP Switch isn't requiered.

thanks for project.
matt

https://dosreloaded.de/forum/thread/7547-comp … 2935#post302935

newer repro doesn't have resistor for config. (DIP Switch on place, is not requiered for 256kb L2 )

greetings
matt

Hello,

I purchased a NOS Compaq PRESARIO CDS 954 awhile back and just recently set it up. This model has a cache card slot. Are any more of these reverse engineered cards available? This model calls for a 128 kb cache. Thank you!

take good pictures of the mobo, good light and high resolution to be able to see individual tracks and chip markings

The DX4-100, which must be AMD, has only 8 kb of WT cache and has the performance of my DECpc DX2-66, which has 256kb L2 cache. This is awful and a complete surprise to me. I presume having some L2 cache will help boost performance somewhat, but I wasn’t aware of the proprietary cache card. This sucks as I bought the NOS pc for the DX4-100.

Here I am, 30 years later, getting duped by Compaq marketing from 1995!

Well the did offer Cache module. Im sure they didnt hide it and it was listed in the manual and available in sales channels.
CDS 954 is such an obscure model I cant even find specs or manual for it 😮 having laptop named presario 954 doesnt help 😀

Right, they didn't necessarily "hide" the cache module per se, but proprietary upgrades like that were common back in the day at prices equivalent in today's dollars 3x or 4x what it will cost to build a retrofit module. My beloved (and quirky) Tandy was notorious for that as well.

I have a Mitsubishi MP 386s (16MHz!) that has a socketed QFP100 which made it a cinch to drop in a TI486SXLC2, but there are no SIMM slots to expand its onboard 2MB of RAM. The manufacturer's memory module has proven absolute unobtanium so far. An eBay seller in Japan was able to share a photo of what the part looks like, but damned if I can pick up any trail to find it yet...I considered the idea of following in the footsteps of this thread to come up with something, but I lack the skills.

rasz_pl wrote on 2026-11-06, 13:05:

Well the did offer Cache module. Im sure they didnt hide it and it was listed in the manual and available in sales channels.
CDS 954 is such an obscure model I cant even find specs or manual for it 😮 having laptop named presario 954 doesnt help 😀

Hi,

What I meant was this is a DX4-100, but its performance doesn’t exceed an Intel DX2-66 with a good VLB video card. I’m getting 28 FPS in Doom benchmark and can’t break 50 in 3D Bench 1.0C. I had no idea the DX4-100 had substandard versions compared to the Intel 16kb WB L1 cache model. This CDS 954 was marketed as a DX4-100 but its performance is equivalent to a good DX2-66 machine.

I’m hopeful that if I can find the L2 cache module, I can get some bump in performance.

I found a link to the specs here.

https://www.elhvb.com/mobokive/archive/compaq … quickspecs.html

>What I meant was this is a DX4-100, but its performance doesn’t exceed an Intel DX2-66

Thats on the buyer for cheapening out on the optional Cache. Cache at the time was expensive, cost as much as one CPU speed grade. Might even have been that difference between DX2-66 -> DX4-100.

"128 KB Cache Acceleration Kit" 171018-001
Model awfully close to 197005-001 (003670-001) and 197050-001 (003454-001) that sander wichers cloned in this topic.
We wont know if its compatible until you post good pictures of your board. As is now there are no pictures of PRESARIO 954cds mobo on the internet so we dont even know whats inside.

Hello,

Please see the CDS 954 Motherboard. I would like to purchase a compatible cache card, if someone can build it for me. Thank you!

Yeah, so this is standard https://theretroweb.com/motherboards/s/compaq … -900-series-486 and module from this topic will work with it no problem

rasz_pl wrote on 2026-11-11, 23:38:

Yeah, so this is standard https://theretroweb.com/motherboards/s/compaq … -900-series-486 and module from this topic will work with it no problem

How do I purchase one? I do not have the expertise to build this myself. Thanks!