XG will use as many threads than your computer has, the limit is 64.
Using more threads does make a big difference. In particular, for rollouts (or level such as XGRoller) twice more core is almost twice more speed. 3-ply and lower analyze do not gain as much, but 4-ply and up do.
About hyper threading, do not worry about it, the OS will handle that (developers do not have to program specifically for HT). Note that an hyper threaded core is about 1.3 faster than a non-hyper threaded one.
The following is just a guideline, GameSite 2000 Ltd is not responsible of what computer you ultimately choose.
Intel newest processor (Sandy Bridge) does extremely well in its ratio performance/price
As a guideline, check the Passmark score (
http://www.cpubenchmark.net/) the score scale almost linearly to XG speed (with a factor of 300):
For instance the i7 2620M has a score of 3318 and will get around 1,000,000 pos/sec.
The i7 940 XM has a score of 4506 and will yield 1,350,000 pos/sec
XG speed is 99% due to the processor, memory speed, hard drive speed has virtualy no effect.
XG is a 32 bits program and do not benefit from a 64 bits OS (but run without any issue on Win 7-64). However if you have 4 GB of memory or more, the OS will do a better job to use the memory.