Originally posted by: kmmatney
A real machine will have more crap running in the background, antivirus, skype, messenger, firewall, etc... On the average user's machine, the benefits will be greater than these graphs show.
This is easy enough for anyone to test out. Run your games with all the crap running in the b/g and record the results, then shut everything down and rerun. I'm willing to bet you won't notice a difference. I didn't. Antivirus, messenger, other processes, etc. None of them take up much (if any) CPU time. Granted, I wouldn't run a system-wide virus scan while gaming, or decode a DVD, or burn a disc... but you get my point.
Either way, like others have stated, a new build should include a dual-core processor. They're cheap enough now and it doesn't make much sense to build with single-core unless on an ultra-low budget (but, even then, the savings would be minimal).
Where this info is especially relevant is for those current single-core users thinking that a dual-core might make a night&day difference for their gaming. Take your rig, kmmatney, for example. A dual-core might make things "smoother" as you say, but, really, you'll notice a whole heckuva lot more performance in gaming if you upgraded your GPU instead. If you had $100 to upgrade your machine right now, I wouldn't grab an X2 3800+ to replace your 3400+. I'd save up a few bucks more, sell your GTO and get a GTS, and see a huge increase in performance vs what a dual-core CPU would do for you.
I, like you, am still using single-core in my gaming machine. I might skip dual completely and opt for a quad when I upgrade next (sometime late this year or early next). For my settings and resolution, on the games I play, dual-core really wouldn't help me out much at all. Now, if someone wants to toss me theirs for free, I'll gladly install immediately.