I haven't got any numbers for expect gains with win64. Also the app, ie Maya, would need to be recoded to take the full benifit of q 64bit system.

Personally I would go with the 64bit system, a64 3200+ or higher as it has the 1mb cache and the 3000+ only has 512k, as this would get you performance gains in the future.

I think, I may be wrong, that the 848 is either 533Fsb or a cut down version of the 857 which only allows single channel memory, effectily halfing you bandwith and the main reason for going Intel over AMD XP's.

And yes the there are various forms of Unix which are already 64bit, can't remember which of the top of my head.