Yep, what Cooler said, they seem to OC a good bit better, they run cooler, have the extra cache, and also have virtualization technology. What kind of cooling are you using to keep that 830 cool at 4ghz?? That a pretty high OC for an 830, they don't usualy do that well, and if your temps are high you could be throttling. My 830 didn't even make it to 3.1ghz. The 9xx seem to be hitting 4ghz on stock voltage.