PSU headroom for GPU power fluctuations?

[wpirobotbuilder]

When looking at power supplies, is this kind of thing a valid concern?

 

 

Admittedly I'm not necessarily looking at a 290x, but I wonder if there is a rule of thumb for how much overhead per GPU is needed to prevent power protection circuitry from kicking in.

 

E.g. if I was running at 90% of my PSU's rated capacity with dual graphics cards (PSU chosen based on average CPU and GPU(s) power consumption), could these power spikes cause problems if they caused the output of the PSU to be higher than its specified maximum load, even if just for a little while?

[Lays]

Yes of course, when planning a rig you should always think worst case scenario, not something that's "just enough" 

[Fred Castellum]

Admittedly I'm not necessarily looking at a 290x, but I wonder if there is a rule of thumb for how much overhead per GPU is needed to prevent power protection circuitry from kicking in.

 

E.g. if I was running at 90% of my PSU's rated capacity with dual graphics cards (PSU chosen based on average CPU and GPU(s) power consumption), could these power spikes cause problems if they caused the output of the PSU to be higher than its specified maximum load, even if just for a little while?

If I remember correctly the recommended overheard per GPU was around 75 watts each but its been while so I may be wrong. 

[WoodenMarker]

Depends on the psu. 

People tend to heavily overshoot for headroom anyway so I don't see much of an issue other than for the few who already know they're running on the tight side with a 450w. 

[Vitalius]

Depends on the psu. 

People tend to heavily overshoot for headroom anyway so I don't see much of an issue other than for the few who already know they're running on the tight side with a 450w. 

The reason we do this is because PSUs usually last more than 1 build. Future proofing in a different sense I suppose.

[wpirobotbuilder]

Yes of course, when planning a rig you should always think worst case scenario, not something that's "just enough" 

I don't see graphs like that for many video cards, just the average maximum power consumption when under load in Furmark or Afterburner or something.

[WoodenMarker]

The reason we do this is because PSUs usually last more than 1 build. Future proofing in a different sense I suppose.

Of course. I was thinking the same thing with my EA-750 Green..

Boy, did I 'plan ahead'.. Components are veering towards lower power consumption. 

[Lays]

I don't see graphs like that for many video cards, just the average maximum power consumption when under load in Furmark or Afterburner or something.

 

 

I don't see the big deal in buying headroom in power supplies anyways, it's only an extra few dollars and guarantees nearly anything you do to your rig will still work without any issues/ future upgrades.

 

 

I don't use anywhere near my 1000 watts on a daily basis, but when I heavily overclock I get dam close to it and I like to be prepared for that.

[Vitalius]

Of course. I was thinking the same thing with my EA-750 Green..

Boy, did I 'plan ahead'.. Components are veering towards lower power consumption. 

Think of it this way: It's moving closer to the PSU's best efficiency. Yay for saving a penny or two every month.

[wpirobotbuilder]

Of course. I was thinking the same thing with my EA-750 Green..

Boy, did I 'plan ahead'.. Components are veering towards lower power consumption. 

 

Think of it this way: It's moving closer to the PSU's best efficiency. Yay for saving a penny or two every month.

Or it's an excuse to add more stuff to your PC and increase the awesome.

 

 

If I remember correctly the recommended overheard per GPU was around 75 watts each but its been while so I may be wrong. 

Seems to back up what Tom's saw, does this seem reasonable to anyone else?

[Fred Castellum]

Think of it this way: It's moving closer to the PSU's best efficiency. Yay for saving a penny or two every month.

The day Gold Efficiency becomes standard across all PSUs will be a good day

 

Seems to back up what Tom's saw, does this seem reasonable to anyone else?

I believe I learned about that number from a old forum called Overclockersclub. It was a couple of years back, just some info stuck in the back of my head. 

[Vitalius]

Seems to back up what Tom's saw, does this seem reasonable to anyone else?

All I can tell you is that my rig idles at 90-120w and runs at 350-400w while mining crypto currencies which is a primarily GPU heavy process (100% usage). I have a 290X and 3570k with little else to consume noticeable amounts of power. That was read with a kil-a-watt meter. 

I know that isn't exactly as scientific as this graph (I would love to know how to make one and get this kind of data for mine), but it's something.

So yeah, I think this is reasonable.