Originally posted by: hemi
If the game isn't SMP aware and doesn't take advantage of the dual CPUs, the single CPU will serve you better - purely on the fact that for the money you'd spend on the two Opterons and registered RAM, you could have a faster clock CPU and/or put the money towards a better video card or water cooling (and then OC the sucker more to extend the lead). That said, the majority of games on the market do not support dual procs.
I vote 3500+.
Tom