CPU comparison question

A co-worker an I got into a heated discussion about which CPU would be faster: an old Athlon XP (socket 462) 2400+ (at 1.93 ghz I think) or a newer AM2 Sempron64 3400+ (at 1.80ghz). He said the AthlonXP, I said the Sempron simply because it's like 4-5 years newer and is based on 64bit architecture. But he countered with "64bit only makes a difference with a 64bit OS". So, who's "right"? Are they actually about equal?

 

This would of course depend on the way of measurement, but usually the newer processors are much faster because of new techonology.

Sandra gives Athlon XP 2400+ a 6300 MIPS score in Dhrystone test and 3200 in Whetstone. It doesnt have Sempron 3000+, but Sempron 2800+ which would be close enough I guess. It gets about an equal score.
However, compared in another way, one processor could well rise above the other.

I'd always pick the newer one out of the two.

 

there is always the argument of unlocked vs lockedmultipliers as well. certain models of the barton core 2500 were well known for overclockability until AMD laser cut out the multipliers. The same might be true for the 2400 if its an old enough version but I doubt it. In the same respect, the wattage and thereby how hot it will run as well as the size of the nm process it usess would also be conciderations.
But the biggest + for the sempron is it would work in newer motherboards with newer forms of hardware where as the 2400 would be stuck with agp and early adoptions of chipsets for all sorts of devices (usb/firewire/audio/networking/etc./etc.).