Sure A64 is faster. However, a faster videocard will go a long way.
AXP2100+ &X800XT can often be faster than A64 4000+/P4 4ghz + Radeon 9800Pro. So it's not all about the cpu speed for gaming.
You can always both run 3dmark01 and just settle this. To make the comparison fairer, just use your 5500 videocard in his computer or his videocard in yours. The beauty of 3dmark01 is that it generally tells you the "overall speed of your computer" (but in non-shader intensive/non-DX9+ games)
The socket # just means how many pins are on the cpu itself (which are used to link the cpu to the motherboard)
So I want to stress that for gaming, it is the overall package that matters (and more importantly the videocard). If he has P4 2.66 and something like Radeon 9800Pro, then yes his system is faster.