@Sovieto: I think alot of people (including me) were fooled by the BIG 64bit hype and such back in the day of the N64. The 64 didn't really mean much in regards to performance, it's just something technical that I think hadn't been done before. Obviously I think this was used heavily for marketing, making the N64 stand out and sound very powerful or something.
I thinks the 64 refered to the size of each CPU Instruction. I think this really isn't a big thing, and doesn't really represent anything in regards to performance.
I should make note that the original Xbox has a 32bit based CPU (see http://en.wikipedia.org/wiki/Xbox#De...specifications), and the GameCube has both 32bit Integer instructions, along with 64bit Floating Point instructions (see http://en.wikipedia.org/wiki/Nintend...specifications). Finally, I think most PC's would still use 32bit based CPU's, although they are now moving onto 64bit based CPU's. But I don't think this means much to gaming, well I dunno really.
I can't really think of any big advantages of a 64bit over a 32bit based CPU, only that more data can be processed at once, but this can also be a disadvantage . But I must say I don't know much specific to the subject. Anyhows this (http://en.wikipedia.org/wiki/64-bit) may be of interest to some of yas.
I will also quote something interesting from http://en.wikipedia.org/wiki/Nintendo_64#Trivia
Anyhows don't quote me on any of this :-\.Although Nintendo 64 was touted as being a 64-bit machine (the CPU is fully capable of this), the games rarely use 64-bit instructions. The greater precision or range available with 64-bit data types is not typically required by 3D games, and 64-bit data uses twice as much RAM, cache, and bandwidth thereby reducing performance. In addition, the cost-reduced NEC VR4300 CPU used in N64 has only 32-bit buses whereas more powerful MIPS CPUs are equipped with 64-bit buses.