SLI, why is is working?

something just occured to me. When the 6800 series cards were first released, there was much talk about 6800GT and Ultra SLI setups not reaching their potential because cpus were not powerful enough and so acted a bottleneck. Well if the 7800GTX 512MB is about 30-45% more powerful than the 6800 Ultra, then surely the CPU bottleneck problem must be even more of an issue. When the 6800's came out the FX 53 was the fastest CPU avaliable, and the current fastest the FX 57 only runs 400mhz quicker. The X2 4800 while having much more processing power than the FX 53, isn't a super quick single thread gaming chip, and games don't seem to multithread very well. So if FX 53s were a serious bottleneck for 6800Ultra SLI, then why aren't 7800GTX SLI setups even more crippled by CPU power?

I must be missing something, please enlighten me...

well its a different architecture.. things get processed differently, probably. so they probably have optimized the way the instructions that the CPU gives the GPU are carried out.. i dunno, its just a guess, but it kinda makes sense.. to me anyway

Careface*

7800 series aren't meant to be much different architecture to 6800 series