Are three cores better than two?
Barbarian writes "That's the question that Tom's Hardware asked. They took a dual-cpu motherboard and stuck both a single and a dual core Opteron on the board, for a total of three cores. Does it work? Well, yes, when it's not crashing. It does raise the possibility of tri-core processors whilst we are waiting for the next die shrink."
Most game software is multithreaded. However, it is not multi-threaded in a way that will significantly increase performance given multiple cpus.
As one example, I worked on Diablo II, and it had at least 5 threads (there might have been even more, but I can remember what 5 threads did). I've talked to plenty of other people in the industry, and the story is the same everywhere: multithreaded, but not parallelized in the most cpu intensive areas.
"Who is the Journal of Quantum Physics going to believe?" --Stephen Hawking