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PSU for 6950 crossfire

Cheesepie

Member
Aug 30, 2011
31
0
0
Hi, my setup is:

i5-2500k at 4.8, 1.5 volts
Gigabyte P67A-UD4-B3
4gb 1666 ddr3 1.5v
1 western digital black 7200rpm hdd
dvd burner
Gigabyte HD6950 2gb unlocked
Antec Truepower 650 watt psu

Would the Antec be able to hold two 6950s in crossfire or should I get something more powerful?
 

lehtv

Elite Member
Dec 8, 2010
11,897
74
91
Unlocked and with a heavily overclocked CPU, it's cutting too close for my tastes. Here's a rough analysis for you:

GPU TDP = 160W. Unlocked and overclocked, anywhere between that and 200W.
CPU TDP = 95W, power consumption at 4.8 adds +100W (source for estimate).
The rest ~60W

Total power consumption, assuming 100% GPU use:

  • 480W with CPU stressed to 1/2 and GPUs not overclocked. 74% of rated wattage; ideal would be 50-60%.
  • 560W with CPU stressed to 1/2 and GPUs heavily overclocked. 86% of rated wattage - more than is generally thought as acceptable in the long term.
  • 655W with CPU stressed to max and GPUs heavily overclocked. Peak theoretical power consumption may exceed rated wattage; in an optimal setup it'd be wise to keep this number below 80% of rated wattage. That would mean at least an 850W PSU.
If you reduce OC on the CPU and don't overclock the video cards, it's doable. Otherwise, you should invest in an 850W PSU.
 
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