IBM thinkpad t21 has 2x128 pc100 ram Should be compatible with pc133 but that doesnt boot Tried every variation of ram mixing but none work Please help me. Do i need to update bios or something?

Answer 1

Well, PC133 is supposed to work in the place of PC100, assuming you haven't mixed PC100 and PC133 modules, but some computers, IBM's ThinkPad T-series, especially, are incredibly picky about their memory. Even when memory testers tell you it's okay to use PC133, try to avoid it on the T-series. I recently tried to upgrade my T-22 with 2x256 PC133 ram in place of the original 1x128MB PC100, but it won't boot anymore. It won't complete the POST, at least. This seems to be a pretty common problem with T-series computers, whether it's by accident or design, but most big sources don't seem to mention it. As far as I know, there isn't a BIOS update to resolve the issue, either. If you want to try that, though, you'll need to put the old memory back in first, boot up and then update the BIOS. The drivers are available on IBM's/Lenoco's site, but it's easier to Google them. The relevant site should be something like "www-307.ibm.com/pc/support/" and pretty high up ont eh search results. I don't see how it could hurt to update the BIOS, at any rate. Your best bet, though, would be to return the PC133 modules, if at all possible, and buy some PC-100 ram instead.