Should I use NUMA or SMP with Vista 64-bit?

"Last question first: Yes, Vista does support NUMA (XP professional already did)
In most cases it is beneficial to use the hardwares' native memory mode. 'Optimal' memory bandwidth and latentcy is the result.
The modes access policies can be descibed as follows:
NUMA: use local memory first (fast), if full use foreign (slow)
SMP: map every other memory page to the other CPU, this averages out fast and slow memory access
There are only rare cases where the application access foreign memory in a way that SMP modes averaging out the memory access is beneficial for the overall performance.
Example: Database, that doesn't exceed the memory capabilities of the system but still using significantly more than locally available memory.
If you don't care about memory performance you could have saved the money for the expensive i7 and buy a much cheaper (old style) SMP system and spend the extra money for a team dinner ;-)"