between http://www.sapphiretech.com/presentation/product/?cid=1&gid=3&sgid=1160&lid=1&pid=1487&leg=0
and
http://www.sapphiretech.com/presentation/product/?cid=1&gid=3&sgid=1160&pid=1473&psn=&lid=1&leg=0
cannot ghz edition be overclocked too ?
does ghz does not have open gl ?
First of all, you can overclock any video card.
The only difference between these two cards is the clock speed. The Ghz edition is factory overclocked to 1000mhz while the Ghz OC edition is factory overclocked to 1050mhz. I would just grab a normal card with a nice cooler and overclock it myself.
1) i thought u can not overclock some nvidia cards
2) saphire says the oc edition has OpenGL 4.2
but ghz does not have is it true ?
All current AMD cards are going to support OpenGL 4.2. These cards are exactly the same except one is overclocked 50mhz higher than the other.
The only cards you might not be able to overclock are shitty entry level cards that you won't be able to game on anyway.
All video cards worth anything support OpenGL. On Linux, you can even get (slow) OpenGL without a video card.
When people say a card "can't be overclocked", generally they mean it can't be overclocked very far. AMD cards in general, and the 7000 series in particular, overclock very well, as long as it has a good cooler, and both of the ones you linked to have good coolers.