The performance would be similar, but since I'm an overclocker and know the 2.6C can hit 3250MHz (while the AMD overclocks a little worse), I'd probably go with the P4.
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Their performance should be about the same. The 2.6c though I believe would overclock better than the 2800+ and also, Intel's platform will give you more upgradability options for the future (in case you are interested in that). I'm too bored right now to check the prices but if it's about the same, I believe go with the 2.6c.
On the other hand if you want to save money and still get an excellent CPU, go with AMD but buy 2500+ instead. Overclock it to 3200+ and you 'll have a great system with very little money.
Dunno if I'd only use 1 site to make my decision (esp not those links). But yes, look at a few web sites to base your opinion on. And you'll have to look specifically at gaming.
I would say AMD, but that's my personal opinion and it's not based on anything specific. I just like the CPU and it does what I expect of it. In the end you have to make a decision. Don't just believe anyone - make sure you do enuff research.
If you feel Intel is your chipset - go for it - it's YOUR decision in the end and YOUR money.
According to www.anandtech.com, and their testing, the Intel 2.4c Gig P4 is almost as fast as the 2.8 Gig AthlonXP. In some benchmarks it was even faster. Might be the particular benchmark they used for Quake III, and splintercell. The P4 800 Mhz processors seem to be a bit better than the AthlonXP in gaming performance.
This is where you have to go to price and see what the difference will be, and then decide what you want to buy.