This modules is kind-of special, because it has four banks of 32MB each, but while PS/2 SIMMs can be "double-sided" by design, they can not be "quad-sided". So this module uses 6 12-bit switches to select which "bank pair" should be accessed. While the design of this module might try to be transparent to the host about the "quad-bank" design, I have no idea how they could implement that without another (custom) logic chip, so there are reasons to believe that this module is not a standard "36-bit PS/2 module", but some very special HP kind of PS/2 module that requires dedicated mainboard support.

Most likely, it will not work on a consumer-type mainboard, even if it is "pro grade" like the P55T2P4.

There are a few on ebay for ~$20 each

Try it out. grab a pair and see what happens. it looks like a ecc/reg simm. So another issue is mainboard compatibility with registered ram. Some chipsets are okay with it. Some are NOT. I dont recall about the 430HX.

Third. the 430HX chipset is DOG SLOW if the mainboard does not have a provision to upgrade the tag ram. Check this first. If you cant upgrade the tag ram, you should keep this chipset at 64MB of ram (or less)

luckybob wrote on 2023-11-23, 18:33:

it looks like a ecc/reg simm.

It's not registered. The CBT16212 chips are no latch chips, as would be required for a registred SIMM. Also, the CBT16212 chips are no buffer chips, as would be required by a buffered SIMM. They can be used as 24 on/off-switches, or 12 A/B switches, but don't provide any active signal processing.

oh, i did not look that carefully at the HP simms.

If that is the case, I would bet the house they are only going to work on specific HP systems. And I would not be surprised if they caused damage to non-hp equipment.

Hello folks,

thanks for your quick replies. I'll just buy a pair in the bay and give it a try. No risk - no fun. I bought a P55T2P4 on ebay a few weeks ago for very little money, it looks very badly aged and I had to repair it on the I/O chip to get it working again. So it's a good patient for the test.

I'll let you know if it works 😉

Best regards,
JF