Well, put it this way.
I've seen benchmarks so far which use Prime95 to use both cores to 50% (100% for a single CPU)
This (load balancing) is the ideal way to do it IMO because you will still have at least 50% of one core to play games on.
SETI running 24/7 anyone?
My next upgrade will probably include one of these chips, I've already found a buyer for my Athlon64 FX.