Is my psu causing random crashes?

[Anjo206]

I just recently built a gaming rig with 2 GTX 570's in SLI, however running one of them, the system doesn't crash, however no BSODs ever, only freezes that need a hard reset.

The crashes with only 1 GTX 570 don't happen in game, only when im web browsing.

However as soon as I put in the second card and enable SLI, windows still works, but as soon as a launch a game, the system locks up within a few seconds.

I have tested every component, and each one is working fine, I am down to suspecting the PSU.
The PSU I am using is this:
http://www.ebay.com/itm/200698187442?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

However, if I dedicate one of the cards to Physx, it behaves as if there's only 1 card, so it crashes only when web browsing.

 

[ko888]

For a system using two GeForce GTX 570 graphics cards in 2-way SLI mode NVIDIA specifies a minimum of a 800 Watt or greater power supply that has a combined +12 Volt continuous current rating of 55 Amps or greater and that has at least four 6-pin PCI Express supplementary power connectors.

Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Total Combined Continuous Power/Current Available on the +12V Rail(s) rated @ 45-50°C ambient temperature, is the most important factor.

Your 800 Watt Kentek PSU is grossly insufficient to power a system using two GeForce GTX 570 graphics cards in 2-way SLI mode. And no you do not add the 28 Amp max ratings from both +12V rails together (i.e. that's a classic newbie mistake). These power supplies are sold to customers that don't have any idea of how to properly select a power supply.

A reputable name brand 800W power supply would have a combined +12 Volt continuous current rating of 66 Amps and would have at least four (6+2)-pin PCI Express supplementary power connectors.

Don't cheap out on the PSU.

 

[Anjo206]

So then how do you determine if a PSU has a 'combined' +12 Volt current at 66 amps?
Thanks for the insight by the way.

 

[ko888]

So then how do you determine if a PSU has a 'combined' +12 Volt current at 66 amps?
Thanks for the insight by the way.

A reputable brand PSU will actually specify the combined +12 Volt continuous current rating on its label.

A crap brand power supply won't provide the value because they don't want the buyer to know just how under powered their combined +12V rails really are.

 

[Anjo206]

Okay, so would this be enough for 2X GTX 570's in SLI mode?

http://www.newegg.com/Product/Product.aspx?Item=N82E16817121069&name=Power-Supplies

 

[ko888]

Okay, so would this be enough for 2X GTX 570's in SLI mode?

http://www.newegg.com/Product/Product.aspx?Item=N82E16817121069&name=Power-Supplies

I would be leery of the 1 Year Warranty on that PSU. It tells me that the manufacturer isn't confident in its reliability.

My suggestion is this one:

Antec High Current Gamer Series HCG-750 750W ATX12V v2.3 / EPS12V v2.91 SLI Certified CrossFire Certified 80 PLUS BRONZE Certified Active PFC Power Supply for $89.99 ($69.99 after $20.00)
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371049

It has a combined +12 Volt continuous current rating of 62.5 Amps, has four (6+2)-pin PCI Express supplementary power connectors and comes with a 5 Year Warranty. The OEM is Delta Electronics.

 

[Anjo206]

But is 750 watts enough? I have a 7200 rpm hdd and a CD/DVD optical drive with a Phenom II X4 cpu.

I'm worried it might not be enough.

 

[ko888]

But is 750 watts enough? I have a 7200 rpm hdd and a CD/DVD optical drive with a Phenom II X4 cpu.

I'm worried it might not be enough.

Did you read my first reply? There's a reason why I stated the following:

Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Total Combined Continuous Power/Current Available on the +12V Rail(s) rated @ 45-50°C ambient temperature, is the most important factor.

Those that select a power supply based on its total wattage alone are the ones that run into problems because they don't have any idea what makes a power supply adequate or inadequate to power a system.

The CPU and graphics cards are the devices that consume the majority of the power in a system. Both of those devices obtain all of their power from the +12V rail(s) of the power supply. The HDD, CD/DVD drive, cooling fans have a relatively miniscule power consumption from the +12V rail when compared to the CPU and GPUs.

The Antec High Current Gamer Series HCG-750, that I recommended, is highly overspec’ed and has been tested by a reputable power supply review site, where they were able to pull 987.4 Watts from it.

The power supply calculators that some use are essentially useless because they don't specify the minimum electrical current capacity required on each output rail for the wattage that they calculate. This just misleads the customer into buying the wrong PSU.

 

[Anjo206]

Best answer selected by Anjo206.