Libreboot shouldn't have anything to do with it. If you have to ask for information and don't know what you're doing, this is not something I would recommend attempting.
I was trying to inb4 someone tells me "install libreboot+gentoo."
The wiki says:
>"It is believed that all or most laptops of the model T400 are compatible. See notes about CPU compatibility for potential incompatibilities."
and there was a small reference to using a quad core on the t400
>"Very likely to be compatible, but requires hardware modification. Based on info from German forum post about installing Core Quad CPU on T500 found in coreboot mailing list. Currently work in progress and no guide available."
Anyways I have a few other computers that I wouldn't mind messing up.Right now I'm just interested in learning.Thank you for the previous advice btw.