You can - the K is much better suited to it, but sometimes you can also crank up the FSB to a certain extent. You can also OC your ram.
Looking around a bit more, it seems people have had some serious luck with the 6500k, but it's also considerably more expensive.
You'd also need a board that supports it, and if you were going to buy this chip and seriously OC it, you'd want some extra cooling.
You should really decide what you're trying to accomplish first. If this is your first build, I would just get the 6500 for the time being. You can always get something else later on, and that one ain't bad for $75 or so.
Check out these:http://www.overclockersclub.com/pages/overclock_faq/
(a little dated, but nice and simple)http://www.overclock.net/amd-general/91-ul...king-guide.htmlhttp://forums.extremeoverclocking.com/showthread.php?t=79266