Help overclocking 6950 Asus DirectCU II

So i have a fairly old system and i want to be able to play BF4 with a decent frame rate(50-60) on high settings. currently i can get around 38-45
I dont have any experience overclocking graphics cards.

Ive tried using amd catalyst overdrive.
clock to 890
mem to 1280
with the power to about +7%

so i know increasing the power isn't the same as increasing the voltage to the gpu. with this ive been able to play bf4 fine(without crashing) but i wanna know weather its necessary to increase the voltage if so by how much and also how high of a over clock can i have and not affect the lifespan of my card.

I know i can use some third party apps like msi afterburner to overclock but i didnt use it because i wasn't tweaking the voltage.

any advice appreciated. Thanks

lucretius, welcome to the forum.

If you have overclocked it and it's playing BF4 to your satisfaction, ie. not artifacting or crashing, then no there is not any need to increase the voltage. If you find you start having issues or you want to push further then you may need to start increasing the voltage.

Can you flash your 6950 to a 6970? I'd try that first, then look into overclocking.

For my 6960 --> 6970 mod, I think it was the cooling of the VRM's that was holding
me back, because once I mounted a high power, high noise, high RPM fan right over
the VRM's I was able to get another 24Mhz out of my core overclock and get my
RAM to 1450Mhz. Of course, I'm not using the stock cooling solution, but an Arctic
Cooling Accelero II Extreme.