What happens when your SLI setup pulls more power than the PSU can provide?

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SubZero
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What happens when your SLI setup pulls more power than the PSU can provide?

Would the system just shut down? Would you have to turn the switch off and on manually on the PSU to get it to respond?

Also, what happens when your system overheats? Would the system also just flat out shut down?

Thank you for helping

Vortex88
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Well I'm not sure about the psu thing. I think with that you just wouldn't get the same performance out of your hardware.

When it comes to overheating though, there should be a setting that you can mess with in the bios so that if the motherboard or cpu gets to a certain temperature it will automatically shut itself off.

slugbug
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If your CPU overheats the computer will simply shut down to prevent damage. Your motherboard's bios handles that.

Razear
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The PSU would shut down due to overload protection.

Dj Neta
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most PSUs have undervoltage and overvoltage protection so it should be ok. they system simply won't start.
if your system dosen't start cuz you consum more power then you can actully get, try lending or buying a stronger PSU and connect it to your system. if it works "Walla", if not, then somthing else may have gone bad.

Dj Neta =)
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SubZero
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Thanks for the replies. One of the things that can happen, I've learned, is that the PSU can just shut down the entire system when too much current is being pulled and force you to switch the PSU off and then on again. Sort of like tripping a breaker at your house. Replacing the PSU with a unit that has sufficient capacity on the 12v rails can avoid the issue entirely, it would seem.

SubZero
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I replaced the 700w that had 38/41 on the 12v Rails with an Antec 750 True Power Blue, and it has 25a on each of the 4 12v rails. It has 2 rails dedicated to PCI-E, so they plug into the GTX 295 and I'm good to go. Have not had a single issue such as before since the Antec was installed.

SubZero
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Confirming that there is still no issue since put in the new PSU.  It's working like it should, and that's nice...

mimart7
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A single rail is far better than a multi rail psu, anytime. It is always better to have a psu than far exceeds your needs than one that just meets them,imo

"Real men do it with their bios"

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SubZero
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It does sound less complicated to have that single 12v rail. I just happened to find a trusted brand name locally and decided to go that route for the sake of convenience.  Next time, I'll look more closely at other options.  I just dropped the ball on this one.

Kindom934
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I like the Cosair psus for that. They got one big huge rail VS multiple.

 

Earlier PSUs that were supposely 'SLi/Crossfire Ready'...even with multiple rails adding up to 40amps+ had issues running SLi/Crossfire back in 2007. They had enough 'total' amps, but they couldn't adjust the load fast enough causing the system to just shut down. Now days power supplies should run stuff fine as long as you meet the minimal requirement.