Trying to upgrade my notebook processor (478 OR 479)

Kinda confusing, but the 479 is the mobile version of the 478 socket desktop family.

You say you got all the info.. from Sony? What info are you referring?

What CPU are you changing out for the T5500, or are you upgrading the T5500 to something else?

Also did you check if you needed a bios update in upgrading?

Actually, there are both socket 478 and socket 479 Pentium M CPUs. I don't know of any core duo that came in 478. 478 was used in all Banias Pentium Ms and I believe a few of the low end Dothans (400fsb) and all the Celeron Ms (both Banias and Dothan).

I have a T5500 and am trying to upgrade to the T7200 (2 GHZ 4MB L2)

It's actually Socket M, which is Socket 479 version 2.0. Socket 478 and 479 are physically similar if not identical, but wired differently. The original 479 and your Socket M are a tad different in the pinouts, too.

I have an old Pentium 4-M that is a socket 478 chip yet the socket says 479. Why? Perhaps the manufacturers were making the ZIF part of the socket for the yet-unreleased Socket 479 Pentium M Dothan a bit early?

This man is correct.

Socket 479 is a mobile socket type, Socket M is also 479 pins but, as MU said, a different pinout. If you have a newer Pentium M, Core Duo, or Core 2 Duo, you have Socket M.

Thank you guys, its already caming down the pipeline and should be installed in my laptop tomorrow