Fastest of all lines of the chips:
Intel Xeon (designed for servers):
3.0 Ghz
Opteron (designed for servers in SMP use, but appears to be a great performer; uses 64-bits as opposed to 32-bits yet can run 32-bit programs very well):
Opteron 144(for one processor)-1.8 Ghz
Opteron 244(for 1 or 2 processors)-1.8 Ghz
Opteron 844(for a whooping 8 processors)-1.8 Ghz
more info here:
http://www.amd.com/us-en/Processors/...6_9240,00.html
AMD Atholon XP:
Xp 3200+
Pentium 4:
3.2 Ghz
Via-Cytrix (*giggle*):
700 mhz
Celeron:
2.4 Ghz
Duron:
1.3 Ghz
Pentium III:
1.4 Ghz
486 (just for fun):
486DX/4-100mhz
Between the XP and the Pentium IV, check out Tom's head-to-head:
http://www6.tomshardware.com/cpu/20030623/index.html
Hmm...apears the 3.2 is faster. However, on the SETI test a machine with 2 Opteron 1.8s (probably the 244) smoked the Xeon competition.