Overclocking to 1Ghz on 7850/7870

I'm going to be getting one of the above cards for my pc one I get a little more money together and from what I have read most of the higher end AMD cards OC really well to 1GHz.

So my question is, will a XFX 7850/7870 DD Edition or Sapphire 7850/7870 (dual fan cooler thingymawut) get to 1GHz and if so, is it just a matter of upping the core clock on the card and bumping the voltage up a bit?

Pretty much yeh. Get MSI Afterburner, it's dead easy to do