I have 600W power supply (OCZ Stealthxstream 2 600W) in my pc. I use currently Asus Radeon HD 7970 graphics card but would like to buy second card (GTX 970) and use both cards at the same time at full power (but not overclocked).

When this one card I have is used at full capacity I measured that computer draws around 245W of power. The second card power requirements are around 150W.

I have only three 4-pin molex connectors free left (two are already used to power first card) and the new card would require two 6-pin connectors. Could I split one 4-pin into two 4-pin connectors and then use two 2x4-pin to 6-pin adapters?

Would I be able to use current power supply in this setup?

Edit: with all four CPU cores at 100% the power consumption is right now around 303W, but I don't expect to use that much.

  • 3
    Possible duplicate of Graphics card and PSU requirement – fixer1234 Mar 14 '16 at 20:52
  • It won't work. Will crash at peeks. How do you want to use both cards at the same time anyway (just curious)? – Flash Thunder Mar 14 '16 at 21:06
  • 1
    Not enough of the proper connectors on the power supply is a bad sign. – Musselman Mar 14 '16 at 23:17
  • 1
    @fixer1234, answers in those link do not answer my specific question. – Paweł Nadolski Mar 15 '16 at 7:03
  • @FlashThunder, OpenCL/CUDA computations – Paweł Nadolski Mar 15 '16 at 7:03

(edited based on edit of OP)

It will work, barely. If the MB and both cards go to %100 draw, you are in trouble, as that is essentially 600 watts of load.

I strongly recommend either upgrading the psu or using a supplementary psu like the Juice Box, or the epower EP-450CD to power one of the cards.

That rig will not be stable, particularly under high cpu load.

  • 2
    how can you answer that not even knowing the rest of config? 0_o – Flash Thunder Mar 14 '16 at 21:06
  • @FlashThunder, what other config do you want to know? – Paweł Nadolski Mar 15 '16 at 7:04
  • 1
    PC uses up to 300W with GPU and CPU at 100%. Adding second card will make this 450W. PSU is still below 80% usage. So, why this won't work? – Paweł Nadolski Mar 15 '16 at 14:56
  • This is average usage, not at peek. I'm telling you, you'll get BSODs. Try yourself if you don't believe me. – Flash Thunder Mar 15 '16 at 17:46

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