I've been LOOKING to upgrade the CPU on my girlfriend's computer. It has a foxconn motherboard. I've contacted Foxconn and gotten their 'official' list of compatible processors. It indicates the best options are the Northwood pentium 4 478 pin 533Mhz 3.06G CPU, or Prescott 2.8Ghz. I've looked it up, and those are the best/fastest 478 pin 533Mhz Intel made at the time the MOBO was being made. UNFORTUNATELY, since those processors aren't being made anymore, they are outrageously expensive, if you can even find one.
My question is about the Pentium M (mobile) processor line. It appears that the M line uses the same 478 pin slot that is on our MOBO. Does anybody know if the Pentium M 478 pin 533Mhz 3.06G will work in our older PC? The only real difference I can find between the discontinued Northwood CPU and the Mobile one, besides being MUCH cheaper, is that the Mobile has a 1M L2 cache, while the Northwood was only 512.I've never TRIED it myself, but the Wikipedia article on the Pentium M suggests that it won't fit straight on to the board. However, ASUS makes an adapter of sorts to fit a Pentium M onto an ASUS Pentium 4 board (like you're trying to do).

http://en.wikipedia.org/wiki/Pentium_M

-=EDIT=-
That adapter apparently only works on ASUS boards.The pentium M is an entirel different CPU to the P4-M.
Are you looking at the mobile P4 or the P4-M?
http://en.wikipedia.org/wiki/Pentium_4#Mobile_Pentium_4Sorry for the confusion. Advertisers can be a little vague. Looking at the list of Pentium 4 CPUs the 478 pin 533MHz fsb isn't a 4-M. I made the mistake of thinking the M line was all of the 'mobile' processors. Sorry.

http://en.wikipedia.org/wiki/List_of_Intel_Pentium_4_microprocessors

If you look at Intel Pentium CPUs with 478 pin, 3.06G and 533MHz, you'll find 3 I believe. One listed under standard P4 CPUs and two listed as Mobile. I've looked in many places online and written many people and get completely opposite answers depending on where I look, or get no answers at all. Some websites indicate that the 478 pin P4 and the 478 pin Mobile CPUs use the same socket (mPGA478B), and that all 478 pin CPUs will fit even if they won't all work. Other websites indicate that an adaptor is needed, if even available, because the 478 pin for PCs is different than for Mobile 478 pin CPUs.
I've written both Foxconn and Intel several times, and both say that there is no GUARANTEE that a new CPU will work on an older MOBO, always avoiding the question of whether or not the mobile 478 will even fit in the same socket.
If a 'mobile' 478 pin P4 CPU will fit in the older 478 pin P4 socket, the next question will be whether or not it will work. It seems to me that if the speed, fsb, etc. all MATCH original specs, that it should work, but I don't know. I've considered just buying one to try it, but I hate to waste money. I suppose I wrote this question to see if anybody else had tried it.
Foxconn definitely says that the Northwood P4 478 pin, 533MHz, 3.06 CPU will work. The question is whether or not the mobile P4 with the same specs will work or not.
Sorry again for the earlier confusionIs the voltage the same? Laptop processors run at lower voltages (to save power). Sticking that into a regular system board could fry it if the voltage is too high.Take a look at this.
Hope this helps.