Probably not if that's a desktop Pentium 4 processor (I believe the only Dell models using a "desktop" Pentium 4 processor is the XPS and 9100, but I have been wrong before *;-).

The pin number is the same (478) for both mobile Pentium 4 and the desktop Pentium 4, but you'll need to make sure you get a mobile Pentium for a laptop as the desktop version runs at a higher voltage (not sure if the pin "arrangement" is different between the two...somebody may step in here with that tidbit).

The C640 uses the Pentium 4-M processor (Mobile Pentium 4). Not to be confused with the Pentium M (aka Centrino) which is the low voltage Intel processor for laptops.

From the link above for the C640 it appears a 2.2 GHz is the max CPU as long as it is a Mobile Pentium. Didn't see the breakdown in the Dell C640 specs I have archived, but I'll take C/NET at their word until proven otherwise. Edit: I rechecked the Dell Tech C640 specs and saw it also will run a Celeron, although I doubt anyone would go that route for an upgrade (downgrade). *;-)

Also look at the lowest wholesale price (not auction price) you found for the microprocessor...if it's around $200 to $220 it could be a 4-M 2.2 GHz for laptops. If it's $130 to $180 it's probably a desktop Pentium 4.

HTH,

Texruss

Message Edited by Texruss on 03-27-2004 10:22 PM

It'll work - if it's a mobile Pentium4-m CPU.  If it's a desktop CPU, it won't work.

Price is one guide - if you're buying new, a 2.2 mobile P4-m will run $200-250.  If it's $150 or less, it's the desktop version and won't work.

Aside:  The Inspiron 1100 and 5100 also use desktop P4 CPUs;  the 5150 uses a mobile P4 (without the -m), which is yet another incompatible P4 CPU type.

Message Edited by ejn63 on 03-28-2004 11:24 AM

>The Inspiron 1100 and 5100 also use desktop P4 CPUs

Thanks for the information...I guess that's why those babies run fairly hot. *;-)

Cheers,

Texruss

Thanks Tex,

I was wondering myself, I was looking to upgrade my CPU and power supply on my c640.

I don't like the centrino processors.

thanks