I want to Overclock my GPU

[Danoded]

I have a Sapphire Radeon 7870 HD GHz edition and I want to overclock it using MSI Afterburner (and maybe the AMD CCC). It is brand new as I only recieved it 2 days ago. I would just like to ask a few questions

I have a 500w PSU is that enough to overclock it?
What are the settings which I should overclock it to which are safe and considered the "sweet spot"?
What are the perks (in terms of gaming) of overclocking my graphics card?

My system:
GPU-Sapphire Radeon 7870 HD GHz edition
CPU-FX 4130 3.8GHz
MOBO-Biostar A960D+
PSU- Coolermaster Elite Power 500w
RAM-8gb DDR3 1333Mhz
Monitor- 1920x1080 60Hz

I've heard AMD cards are beast at overclocking and I want to get the most out of mine so any help would be appreciated since I am quite new to this. Thank you.

 

[IRONBATMAN]

Coolermaster's PSUs are terrible. It is not an ideal PSU for overclocking. But its ok if you just wanna overclock by a bit

 

[lukapavlinovi]

Don't ever max out OC on afterburner or any other program. Try to OC a bit and always be careful to keep system stable. As for PSU you should take Corsair 600w PSU. Then you could OC more without worries. And in future take at least around 100w more PSU than needed. That way you can OC GPU nicely, no doubt.

 

[icraft]

It should be ok. If you get random shutdowns it might be a PSU issue, but the 7870 is not a power hog.
You overclock by setting the powerlimit to +20%, then increase the core by 10mhz until you get instability in a game, then lower it by 15mhz. Do the same with memory. This is a rough guide, so you will probably want to read up more. A sweetspot tends to be around 1100, but it is very random. You will get more fps.

 

[Danoded]

It should be ok. If you get random shutdowns it might be a PSU issue, but the 7870 is not a power hog.
You overclock by setting the powerlimit to +20%, then increase the core by 10mhz until you get instability in a game, then lower it by 15mhz. Do the same with memory. This is a rough guide, so you will probably want to read up more. A sweetspot tends to be around 1100, but it is very random. You will get more fps.

After I've finished with the overclocking do I reduce the voltage? And what should I set the core voltage to?

 

[icraft]

Core voltage should either be 1.2 or 1.25. I would keep whatever is stock.