Looking at the hoursepower of the server: what's better 2 64 bit CPU or 4 32 bit CPUs?

4 32bit cpus. Words are rarely 8 bytes long. Typically they are 2 or 4 bytes long otherwise they would have came out with 64 bit processors after 16 bit processors. It could be faster moving memory but graphics cards should contain this function thus eliminating the need. Memory Page access, like cache loads, would be faster but I doubt the processor could do enough with that page to make it count.

a bit thin on your request, which 32 bit processer, which 64 bit processer? in what settings? anyway, given exactly the same main logics, the same clock speed, a 64 bit processer would most likely run a little faster than a 32 bit processer. in those few instances where a piece of data is bigger than 32 bits, the 64 bit processer will do it faster (I.E. double integers). given any other advantages, like a 64 bit main data buss, the 64 bit processer will blow the doors off a 32 bit processer. 64 bit chips were not built right after 16 bit chips for 1 reason, cost, there is more than twice the number of circuts in a 64 bit processer than a 32 bit processer.