May need to upgrade PSU...

SomeOldBloke

The PSU I currently have is a PC Power and Cooling 750W from original build when I had a core2due E8500 and a HD4870 back in 2008. Bought at the time to allow me to upgrade for several years without having to worry about it. I'm now running i7 2600, GTX670, 12GB on a MSI Z68A motherboard. It runs fine on with this setup but I just ordered another GTX670 to SLI for BF4 and although the Newegg PSU calculater says I can do it I'm wondering if I need to upgrade, especially as my PSU is nearly 5 years old.

Opinions?

Ridelynn

Well, idk about Newegg's calculator, but my formula is

TDP of GPU(s) + TDP of CPU + 100W (for everything else; motherboards, fans, HDDs, etc)

Mutliply x2 if your overclocking any component.

CPUs are usually around 100W, your i7 is 95W at stock clocks

Your 670 is 170W at stock clocks.

So,
170 + 95 + 100 = 365W
That your using right now, with nothing overclocked

Add another 670 in there, your at
170 + 170 + 95 + 100 = 535W
With nothing overclocked.

Under normal circumstances, I would say 750W would be plenty so long as you aren't overclocking.

Now overclocking there is no hard and fast rule for how much your TDP will go up by, it varies based on silicon and your specific chip, but x2 is a conservative estimate. You can see that if you plan on OCing those video cards, the power requirement could go up very fast.

There is also the matter that ~most~ power supplies straight up lie about their capacity. Many label themselves as 750 (or what have you), but can really only put out about 550 or 600 before they start to crap out (either overheat, voltage goes out of tolerance, etc). Many "calculators" take that into account, and seriously overblow the wattage you need.

Now this isn't the exact same model, but it does bode well for your current power supply:
http://www.hardocp.com/article/2007/08/03/pc_power_cooling_silencer_750_quad_crossfire_edition/9

It passed, and got a Gold review from HardOCP... so I would say your existing power supply has a leg up on most, and probably could actually put out 750W (or at least close to it).

So, all of that given. I would say, your not having any problem with it now, it probably will be fine so long as you aren't overclocking anything. But, if you have the money, or especially if you plan on overclocking, it would be a good idea to go ahead and get something new just to be certain.

SomeOldBloke

Thanks... as I'm not overclocking and I don't plan to everything should work... famous last words.