With that setup, i wouldn't want to risk it. While XFX PSU's are capable, you'd be stretching it far by adding another 5970.
Mind if i ask why you'd want another 5970? Quad Crossfire drivers are rife with issues to the point it's barely worth it. Not to mention that the 5970, coupled with a potent CPU like yours will rip through anything that gets thrown at it. You should OC the CPU as well with a decent cooler, that will eliminate any semblance of a bottleneck.
You're best off selling it and putting the money away for a rainy day.
Im rather scared of OCing, ive allready burned a motherboard an a i7 920 and somewho my PSU went too while trying. I just used the motherboard preloaded oc settings (the smallest one). Went good for like 20 min, then it said black screen of doom. and never went on again.
And about why im getting a another 5970 for Quadfire, i just want to try it out. And run some games with 3 screens. I can allways sell it afterwards again =)
Sounds like a bad PSU that caused that last burnout, either that or a bad motherboard. Was either one of them a questionable brand / quality?
From what i've read, the XFX PSU's are very capable and are very unlikely to blow out if you try and OC this one. You haven't listed your motherboard, but i think even a basic one from a decent manufacturer will be capable enough to have a mild OC.
Anyway, fair enough if you're wanting to go over 3 screens, it seems a little more feasible now, but it will still tear through that resolution though.
But back to the original question, i'd upgrade your PSU to something like a 1KW one, maybe an Enermax Revolution 85+.
My old motherboard was a Asrock x58 deluxe, with a Northq 800-900watt (cant remeber the watt) PSU.
Then i got my hands in a Asus Rampage III Extreme that was doa, and they didnt want to RMA it. Because BIOS 2 chip was damaged somehow. And they said i must have done it. I unplugged the bios chip from the socket when i got the board back from the RMA. And noticed 2 of the 8 pin was bend in under it. And never plugged into the socket, tryed to put the pins back in the socket but didnt work. So i changed hardware shop.
So now i got a Asus sabertooth x58 motherboard.
About the 1k PSU will it could handle it? i dont wanna take chances. I dont really wanna end up with two psu´s =)
A 1000 watt should be fine for two HD 5970 cards, as long as its a quality one. Just make sure before buying one that you check reviews for it fully before buying to make sure it can sustain its promised wattage. There are quite a few crappy and subpar 1000 watt power supplies on the market that barely pass the test.
There you go. ASRock are hardly known for their motherboards and NorthQ are half a step away from being a generic brand.
Just for reference, the Asus Sabertooth will actually hate you for life if you DON'T over clock on it. It's what it is designed for.
If you had just one hard drive / SSD then I would have said that you may be able to squeeze it in. But because you have a multiple drive system, they will take their fair share of power that would take the PSU over the limit if you added a 5970 into the mix. I genuinely think you should play it safe and go for a 1 KW one to be on the safe side. Otherwise you may get a similar result to what you had before...
I'll just put some hard numbers out there for you.
The typical power draw of a stock clocked 5970 is 294W, times that by two and you have 588W.
An SSD will typically consume about 35W, times two is 70W.
Your typical hard drive will consume between 50 and 60W, times four is between 200 and 240W.
That CPU will take anywhere up to 130W.
All these added together brings you to 1040W, so you're going to need a 1KW or above PSU to handle it.
Good choice with the PSU, quite an investment though so do look after it!
Pointers with OC, start small and go up in small increments.
On a decent air cooler, the 950 should be able to hit 4 Ghz easily, but if you're not that brave, 3.5 Ghz is a very reasonable target.
Always try to overclock using the FSB (otherwise known as BCLK), it will also increase the speed of your RAM as the two are interconnected as they are with the CPU, so make sure the speed of your RAM is within it's limits. If it goes over at any time, reduce the memory multiplier to put it within its confines. In terms of voltage increases, you only need very very minute increases, Google should be your friend there. Also make sure that the DRAM (memory) voltage is set to it's safe maximum, for DDR3 it's usually 1.5V or in some cases 1.65V, check your sticks for what that will be.