Just installing a true P4 vs a Celeron will make a difference. As for the P4 upgrade, just install one for 478-pin setup. If anything, if it doesn't work, but it may and that depends greatly on how the FSB will handle the multiplier aspects, from 2.4 to 3.0. That means the bios(latest update) must be capable as well as the mtrbd.(FSB) of accepting the newer cpu. Even though it will drop-in, the fastest the mtrbd. will ever be presents itself. You want a 533 based, though 400 comes along for the ride. What you will find are 800, which won't work, unless they also have 533. The hard part besides finding one, is the Intel part# located on the cpu die will readily ID what you have for 100% certainty. Visit the Intel support website and navigate until you find P4 references(part#), then the listings of what cpu you need to locate. Do notice some cpu support 400 and 533, but avoid any other higher mhz like the 800 which aren't going to work, unless they can support 533 as well. If you're lucky, actually 3.4 is as high you can go with a P4 single core.
If that doesn't seem to work, the Gateway systems tend to lend themselves to mtrbd. upgrades. Finding a used one and being Intel(maker) makes the above cpu upgrades more workable. Older Gateway systems were more generic in make-up and thus user DIY replacing mtrbd., etc., IMHO.
You can re-use the cpu fan, just be sure the thermal paste is good or repaste again. HOWEVER, that fan must be rated for the cpu its installed on. I don't recommend a 2.4 fan be used on a 3.0 cpu. It will fit an all that, but a new fan isn't going to cost much, so take heed. Hypertreading isn't an issue, either it works or doesn't(its automode).
I have a friend with an old computer who would really like his CPU upgraded. He currently has a Pentium 4 2.4GHz chip. These are the specs given for his Gateway Motherboard:
Support for Intel Pentium 4 and Celeron processors
400MHz or 533MHz System Data bus 478-pin zero insertion force (ZIF) socket
We would like to upgrade to a 3.0GHz Pentium 4. However the 533MHz Bus, 478 pin Pentium 4 chips at this clock speed seem to all have Hyperthreading, and I do not think this motherboard supports hyperthreading (its updated to the latest BIOS, but thats still 2003).
The PC is listed as Part Number: 2519530Intel (Essex) Celeron - 2.4 GHz (400MHz) R0
The individual part number for this motherboard is 4000828.
(Info found from http://support.gateway.com/s/MOTHERBD/INTEL/2519530/2519530nv.shtml).
I'm not sure what I can upgrade this CPU to. It also appears many of the possible upgrades are all refurbished without fan or heatsink. Is it possible to remove the old fan and heatsink from the current CPU and put it on the new one? if so what kind of tools and equipment would be required?
Thank you for any help you can give. I'd hate to get a new CPU that "appeared" to fit all the specs but find out that something is not supported and renders the CPU worthless. I'm desperately trying to get this done in the next couple weeks in time for his birthday!