Thanks to everyone.
I was going to go with Gigabyte's HD5670 OC. But I decided to go with a HD4770 and a 550w psu. I think we will be happy since my son and I are only moderate, at best, gamers.
I know this card is oclockable from the reviews.
Unless you volt mod the GPU, it really aint worth the extra 1 or 2 frames.... If the GPU is factory OC'ed then you should not be pushing the GPU farther for a minimal gain. With the volt mod you can achieve a higher OC but you also have the heat factor and voided warranty issue....
I have the xfx 4770 available at newegg. It o/c's from 750/800 to 900/1000. No volt mod. Use Riva Tuner with config file from guru3d.
Without any stability issues. The memory is specd 1000. I've done a bunch of benches it gives a big boost, about 20%. Dirt2 , RE5, 3dmark 06, stock goes from 14000 to 17800. Its a meaningless # , but its satisfying eeking out the extra performance.
Figure the chips that go onto an OC version of the card have already been handpicked to ensure they can run above stock spec. and in most cases the board itself will have better cooling on it - so you should have a better chance of them being able to go beyond what a normal card would go - but as OvrClkr said you probably will only gain marginal improvement at best over what the OC'd board already provides so it is not really worth the effort in most cases.