Frankly, you want more stress taken off of your CPU, that's why GPU's are more complicated than ever, but both work in tandem together. But you will see performance increases in games when turning on the SMP/Multi-Thread feature. Some games like Supreme Commander come with SMP auto turned on and detect how many threads to run or something along those lines. Also game design and system capabilities play a role in how much can be used and how much will be used. Since game designers have to please customers with so many different setups it's tough to make them use each and every PC to it's fullest and have an enjoyable game for at least most of the people who buy it. But with more people on the Dual Core or more Bandwagon, it's getting a-lot better. And with GPU's doing their own "multi-threading" that also helps to more efficiently handle tasks.
