hello people I have an old ibm thinkpad A31 laptop, fully functional. I also have a spare, 1.6ghz dual centrino cpu, same socket 478 mobile cpu. How can I find out if the spare cpu will work on the thinkpad, without opening it up and trying it out? it's the ThinkPad A31 2652-CXG I always say it's best to doublecheck.

There's no such thing as a "centrino cpu". Centrino is the name of the technology package...it's basically a marketing term. The CPU used in a Centrino laptop/notebook is either a Pentium-M, Core 2 Solo or Core 2 Duo. http://en.wikipedia.org/wiki/Centrino I googled your model number & it appears you have a Pentium-M 1.9GHz/400MHz FSB...is that correct? Does your "Centrino CPU" also run at 400MHz FSB or is it a 533MHz FSB chip?

why u yelling at me chief :) not all a31's had the 1.9. mine has a 1.6ghz p4 in it. i'm over the cpu-upgrade rush. it runs well as is. new question about it, maybe you know more than I do about these thinkpads. there's a cover underneath, i opened it, and it has two small cards in there. under the first one, it says Ethernet. but on the card itself, it says 802.3 and then a mac address. is this a wi-fi card ??? because it has a thick antenna-type cable running to it. i don't think it's the LAN, do you? The lan should be a microchip onboard, am I right? I always say it's best to doublecheck.