R50e 1842-T4U: Switching out Dothan Celeron-M for Pentium-M?

[centrifuge41]

I just got a Thinkpad R50e with a Dothan Celeron M 1.4, 14.1" screen, 256MB PC2700 DDR, 40GB HDD, 24x CD, Intel 2200BG wireless.

I'd like to switch out the Dothan Celeron M for a lower clocked Pentium M so I can have speedstep, play with undervolting, and get better battery life. Some R50e's come with Dothan Pentium M's, but I'm not sure whether every R50e has the same mainboard and supports the same CPU's. The ThinkWiki site says that only Dothan Celeron M and Banias Pentium M chips are supported.

Can I swap out my chip for a Dothan P-M, and will I then have speedstep and be able to undervolt the CPU through software like Notebook Hardware Control?

Thanks!

[kyrotech]

well the system board on that R50e uses Intel i855PM chipset, so supports Pentium M Dothan core up to 2.1 Ghz

A friend upgraded from Celeron M 1.5 ghz on his R50e Type 1842 to a Pentium M Dothan 2.0 Ghz, it works great.

[centrifuge41]

Sounds good So the board properly recognizes the Dothan, works well with the CPU's speedstep, and allows software undervolting, right? This is sounding like a good prospect for my new R50e

Edit:

I got my Dothan P-M 1.5 yesterday and popped it in. The system now boots with the Centrino logo instead of a generic Intel Inside logo. Everything works as expected: battery life went from about 3:15 to 4:00 out the box. Speedstep usually toggles the system between 600MHz and 1.5GHz. The fan rarely spins up anymore, as the CPU temp is usually under 50F.

And I've been able to undervolt the CPU from 0.988V and 1.340V (600MHz and 1.5GHz respectively) to 0.700V and 0.940V respectively: a huge undervolt.

[amitra]

http://www.overclockers.com/tips1204/

[geedoubleu-uk]

Is changing the CPU easy?

I've done it loads with a desktop but not a laptop.

Upgrading to Centrino seems like a winner all round for performance when required and battery life.