Difference between these cpus?

I want to know about these CPU`s... Intel® Core™ 2 Duo E6750 CPU @ 2.66GHz, Intel® Core™ 2 Duo E6850 CPU @ 3.00GH

Does Core 2 Duo mean 2 as in 2.66+2.66=5.42GHz

If you've got a game that say for best performance use 3.00Ghz CPU then would a Intel® Core™ 2 Duo E6750 CPU @ 2.66GHz meet and exceed that or what???

A dual core processor doesn't necessarily mean double the speed. It just means that it can split some of the tasks up on either processor, and run the entire computer faster. This means that a 2.66ghz dual core processor is probably much faster than a 3.00ghz single core processor.