[ltp] a21m ram question

[linux-thinkpad@linux-thinkpad.org]

Hello,

I was going to upgrade my A21m to 512MB of RAM.

I picked up something that had matching specs according to:  144pins,
PC100, 3.3V, CL2, non-parity, non-EDO.

It's not even recognized by the notebook.
It's detected by MEMTEST86, but every test fails miserably.
The notebook, when powered up, just sits without even showing it's initial
POST screen.

First conclusion to leap to is that the RAM is faulty.

But before I do that, I wanted to make sure that there isn't anything else
I should pay attention to regarding these notebooks.

Does anyone here have any experience with buying after-market (non-IBM)
RAM for notebooks?  I've upgraded RAM dozens of times on workstations and
even added 64MB of RAM when I bought this one, but the results I'm getting
now are unexpected.