I was wondering if I had say a quad core cpu that was 4x 2.5ghz meaning a total of 10ghz and a game came along requiring 3ghz to run would the cpu run it or would it only access one core and just say not fast enough?

Depends if the game supports multi-core's.

First off, the GHz don't add up in a quad or dual. a 2.5GHz Quad does NOT mean a single core 10GHz CPU. It simply means a Quad that's as fast as a single core 2.5GHz but with 4 of them.

As said above, if the game supports multi-threading, the tasks would distributed among the 2 (or 4) cores instead of 1 core, thus allowing the tasks to be processed up to 4 times faster. However, the game must be multi-threaded, if it isn't, a 2.5GHz Quad will function like a 2.5GHz single core CPU.

However, there are always some programs running in the background, thus additional cores will help alleviate the load off of the CPU, so a dual core would normally be faster than a single core.

Well Generally Faster loading times with quad core.

Thanks for the replies guys/gals, I figured it might be something like that but thought I'd check (after all I guess if they could make a single core that was 10Ghz that easily they would) I guess it's down to theorycrafting future games and whether they'll ask for high speed single cores or lower speed multi-cores.

*Question answered*