Ive been told if I want to improve my gaming on my PC I should be looking to get a new cpu, but what is the difference to games if any , if I have say a "old" 2.5Ghz CPU will it make any difference to the way a game would run if I had a 2.5Ghz Duel Core CPU.

I thought it was more for multi-tasking running 2 or more things at once, and as I would be running a game (single program) it wouldn't matter if I had the old style 2.5Ghz CPU or the new DC 2.5Ghz CPU as its a single program and each run at 2.5Ghz ?

Im not a genius in computers, but I would recomend you to try the game first because I beleive that in this new version any of our "nearly new old" computers should run it with no problem at all.
Maybe for next generation we will have to invest some money (a lot, moreover that in argentina the costs are double o triple).

Any way I still dont beleive much in this dual core computers... I think that it is all marketing.

regards.

Well I am no hardware expert but I'll share what information I can. First, a new single-core processor at 2.5Ghz doesn't even compare well to an old style 2.5Ghz because if I learned anything from shopping for CPU's, clock speed is not a good indicator of absolute computer performance. So, upgrading to a newer 2.5 would be an upgrade in and of itself. Now, you are right in that dual cores are mostly for the benefit of multitasking. However, as dual core becomes more norm, you will see more and more games being developed to take advantage of both and then you will see a significant boost in performance. Right now, though, dual cores do offer a greater performance simply because of a better architecture and allowing a single process to be split over 2 pathways.

So to answer your question, a dual core 2.5Ghz (say a C2D E6600 like I have [which is at 2.4Ghz]) will yield a significant performance gain. I went from an AMD XP2400+ at 2.0Ghz to this CPU and the performance was 2x to 3x better.

Whether you need this performance gain is up to you, the rest of your system, and the software you want to run.

Hope this helps