Kinda depends on your resolution as well as what games. I can't see it bottlenecking below 60fps ever so it shouldn't be an issue at all. But yes, in theory you will be able to get a CPU bottleneck - for example my i5 750 bottlenecked my CF 5850s in FurMark running at only 1280x1050 resolution (5 FPS gain over a single 5850) but then running at 1920x1080 the gain was huge (up to 90% more FPS). So yeah, not really anything to worry about but I would still advise at least a small OC. And guessing you're buying 1600mhz RAM, you'll probably be running a 160 base clock which will give you, with turbo, 3.36ghz and up to 3.8ghz. You'll be ok.
The way turbo works is it boost the multiplier based now how many threads are running. Full 4 core threading will run at 21x but games often only use up to 2 maybe 3 cores so you'll run as high as 24x multiplier. DX11 finally brings useful multithreading tho. But either way, more threads running a little slower is still generally faster than fewer but slightly faster threads.