The methodology: We have a device constantly monitoring the power draw from the PC. We simply stress the GPU, not the processor. The before and after wattage will tell us roughly how much power a graphics card is consuming under load.
 
We'll be calculating the GPU power consumption here, not the total PC power consumption.

Here is Guru3D's power supply recommendation:

• GeForce GTX 690 - On your average system the card requires you to have a 750 Watt power supply unit.
• GeForce GTX 690 SLI - On your average system the cards require you to have a 950 Watt power supply unit as minimum.
• If you are going to overclock the GPU or processor, then we do recommend you purchase something with some more stamina.

RainStryke

 BUT They do provide the full system stress info on a overclocked system. Read read read... 

System Wattage with GPU in FULL Stress = 400 W

RainStryke
Hmm... Do you not see that small part in your quote that says "System Wattage" with the GPU under "FULL stress."

That means, the system under full stress in a game. Real world performance that you should expect to see while playing a game like Battlefield 3.

RainStryke
Scroll up on that page and you can read this: 

Guru3d
We decided to move away from Furmark in early 2011 and are now using a game like application which stresses the GPU 100% yet is much more representable of power consumption and heat levels coming from the GPU. We however are not disclosing which application that is as we do not want AMD/ATI/NVIDIA to 'optimize & monitor' our stress test whatsoever, for our objective reasons of course.

 

The GPU sends the information through the CPU. It has to stress the CPU.

Rei86 

Nice thread man. 

We always have new people asking how much power they will need with their future purchase.   

Great thread RainStryke. 

auraofjason

Rei86 

Nice thread man. 

We always have new people asking how much power they will need with their future purchase.   

Great thread RainStryke. 

 
I agree, it is a great and useful thread, but I just feel like his recommendation of "get a PSU that can operate at these rated wattage sitting at 80% of the PSU's rated wattage" is cutting it way too close, that would mean a 500w psu for a system with a gtx 690 according to these numbers, and he is implying that you will be 100% fine with that 80% 500w stuffs.

RainStryke


My buddy powers his AMD 1090T @ 4GHz, H70, 2 HD6870's, 3 HDD's,  2 DVD drives, and about 6 case fans off a Seasonic X-650 without a problem. These things do not need as much power as people keep saying, it's highly exaggerated. 

lehpron 

  No one is suggesting running a PSU near peak load,

lehpron

Robs03gts 

lehpron  
No one is suggesting running a PSU near peak load,

I didn't say that they were, I was merely pointing out that its a bad idea to do so.

Nor did I say that you have, but if someone only clicked the links and only purchased based on peak load, that isn't smart.  It would make sense for someone to actually read the thread before/while clicking links; at least RainStryke indicated the caveat in his OP:

RainStryke 
Don't cheap out on your PSU. With much lower power requirements, we don't really need a big 1000w PSU to handle two video cards anymore. It's good to get a PSU that would handle these wattages at the highest of 80% load. So if you need 500w, you should look into a minimum of a quality 650w PSU. If you plan on upgrades, move up in size according to whatever you plan. 

80% of load means adding 20% overhead on top of projected requirements.

auraofjason
I agree, it is a great and useful thread, but I just feel like his recommendation of "get a PSU that can operate at these rated wattage sitting at 80% of the PSU's rated wattage" is cutting it way too close, that would mean a 500w psu for a system with a gtx 690 according to these numbers, and he is implying that you will be 100% fine with that 80% 500w stuffs. 

I think people pay too much attention to total wattage and don't look at the 12v amperage need (this is the majority of any gaming computer) since those maximums in PSU's are not the same for every wattage.

GTX690 consumes 300W at reference clocks, or 25A from 12v.  If we add in a stock 2600K at 93W (8A from 12v) with no intention of overclock or Quad-SLI, a single HDD at 1A at 12v and four fans at 0.5A at 12v each-- that is 432W from 12v alone, or just 36A total.  Any PSU with at least that may amps qualifies since most PSU's already take the other voltages into account.  

We can't just deny evidence because we don't like the conclusion, there can be more conclusions from the same evidence.

A Corsair CX500 V2 may have the wattage, 80% BRONZE certified efficiency, and the required pair of 2+6 pin connectors; but doesn't have the required amperage, at 34A on 12v it doesn't qualify.  But a Corsair CX600 with a max of 46A from 12v, Corsair TX650 with a max of 53A from 12v, and Corsair TX650M with a max of 54A from 12v-- all qualify with more than 27%, 47% and 50% more amperage overhead respectively.   There is no need for 700+ wattage units unless there are overclock and upgrade intentions.

Granted, if someone purchased a $1000 graphics card, they would be least likely to get a lower wattage unit based on actual draw with an overhead because they are used to spending a lot of money and uncomfortable with less specs (i.e. making emotional decisions and not logical ones).  

RainStryke

I guess my wording was a little confusing and some people feel the need for extra overhead due to unique needs. I just left out my 20% overhead "opinion" to stop any confusion.

Robs03gts 

RainStryke 


My buddy powers his AMD 1090T @ 4GHz, H70, 2 HD6870's, 3 HDD's,  2 DVD drives, and about 6 case fans off a Seasonic X-650 without a problem. These things do not need as much power as people keep saying, it's highly exaggerated.  

 

Running a powersupply at near peak load for extended periods of time is not recommended, he may not be showing any problems right now but if he is constantly pushing that PSU to the edge then its only a matter of time before it breaks down I would think. 

 

I understand this. But we still have people tossing around the old philosophy to over buy in PSU's, like when the HX1000 came out.

The HX1000 was a good PSU for it's time, but a crap one for todays standards. Out of the box, the ripple levels were around 70mV on the HX1000. Over time it degraded fast due to such a high start point for the ripple levels. It ended up being a 2-3 year PSU.

Better PSU's like the Seasonic X-650 can keep the ripple levels low, even at full load. Decreasing the amount of heat and degradation. You can run a X-650 at full load for a really long time, running at 80% load. Ripple is around 20mV @ 530w.
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story3&reid=169

My friend's crossfire HD6870 machine only uses about 500w adding the extra fans and HDD's.
http://www.guru3d.com/articles_pages/radeon_hd_6850_6870_crossfirex_review,4.html