This is not a good idea. Here's why.
1. Power.
A P3 didn't need a lot of Watts from the power supply. You'll want a new whopper power supply to stay out of trouble. Try 450 Watts so you don't have to revisit this area.
2. Power supply connections.
Most P4 motherboards require the AT12V connection from the power supply. A machine made during P3 days will not have this connection.
3. RAM.
Doubtful you can recycle your RAM. Most P3's used SDRAM, today's P4s take DDRAM.
4. Case issues.
Some machines took a custom approach. Since I can get a 400 or more Watt PSU with a case for the same price as just the PSU most places, I'd just forget recycling those parts.
Hope this helps.
Bob
Hello
I have an older Intel 440BX PMC motherboard (from Gateway named: Jabil BX Motherboard R2)it only supports up to an Intel P3 600Mhz.
I just need to know if I can replace it for Any newer Intel moterboard capable of supporting a P4 processor with greater Ghz?
If not HOW do I determine that? what do I look at when I see the specs in order to determine that?

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