Is 650 watts enough?

**The True Roman** · December 15, 2012, 09:15 AM

I'm about to get anther GTX 680 for Christmas and was wondering can a 650 watt power supply support two GTX 680s SLI'd together? Or will I need more power?

**MrHenry** · December 15, 2012, 09:35 AM

Originally Posted by The True Roman

I'm about to get anther GTX 680 for Christmas and was wondering can a 650 watt power supply support two GTX 680s SLI'd together? Or will I need more power?

According to Nvidia, one GTX 680 AT MAXIMUM needs 195 W. Minimum system power requirement is 550 W. 650W just might be enough depending on your entire system. But I would just in case get say an 800W PSU, I know that sounds insane, but there isn't much price difference and it gives u that much more room to work with

**Totalheadache** · December 15, 2012, 09:58 AM

seems 750w is what you should go for..

http://www.guru3d.com/articles_pages..._review,4.html

and if you oc i'd say the above post is bang on.

**The True Roman** · December 15, 2012, 10:43 AM

If I were to try it would it damage anything? Or would the computer just not turn on? Its just I'm not super computer savy and installing a new Power supply is a little above my pay grade.

**The True Roman** · December 15, 2012, 11:08 AM

I watch some videos and It does matter, I guess I got to upgrade. All well

**MrHenry** · December 15, 2012, 12:23 PM

Originally Posted by The True Roman

I watch some videos and It does matter, I guess I got to upgrade. All well

Yeah bro, lack of power and u could be burning up components

Dont take the risk man

**snuggans** · December 15, 2012, 12:52 PM

Originally Posted by The True Roman

I'm about to get anther GTX 680 for Christmas and was wondering can a 650 watt power supply support two GTX 680s SLI'd together?

absolutely not

**mrmouth** · December 15, 2012, 01:06 PM

It could absolutely be done, but you'd want to do it with a very solid PSU.

The various calculated values put 680's in SLI at under 500 watts at full load. See here. Once you adjust for PSU efficiency (with a good PSU) you can shave another 50 or more watts of the Guru3d number. You just wont be doing any serious overclocking. Like joining an OC club and pushing the limits of your components, type over OC'ing.

So it really matters what brand and model this mystery 650w PSU, is.

**snuggans** · December 15, 2012, 02:19 PM

with 650w you're barely satisfying minimum requirements for two 680's, but then you're going to need to satisfy the power requirements for every other component in his system, and just like you said, he won't be able to overclock comfortably.

use this as a guide: http://www.extreme.outervision.com/PSUEngine

with a high-end motherboard, 2600k, 2 SATA harddrives, and other things expected to be found in a standard case such as fans, i'm getting recommended PSU wattage of 670-680 watts at 90% load and 30% capacitor aging (nobody wants to be buying a PSU each year).

**mrmouth** · December 15, 2012, 02:55 PM

Yeah well all these manufacturer recommendations and guides kind of go out the window when you start measuring voltage from the wall. People have run these cards in SLI with a 650w PSU of good quality.

And again, the capacitor aging talk is one of those things that has crept into this relatively new found phenomenon in buying enthusiast power supplies. You are talking many more years than 99% of people are going to own their PSUs, for. This is again for a PSU with good caps, thermal regulation, etc.

I mean in the industrial sector where many of these high quality Japanese caps were being used before they made their way into beefy PSUs, were seeing caps 15-20 years old that are well within spec. Fractions of a percentage. Not this 10% a year number that has been tossed around.

I mean if you want to start pulling MacII 's apart you might see some capacitor aging to account for.

Anyhow, if the PSU is quality I would at very least try it. And unless I was getting blue screens I would run it and forget about it.

**Crazyeyesreaper** · December 15, 2012, 04:10 PM

well when companies like Corsair are sending review units with all Japanese capacitors but send out retail models with cheap Chinese capacitors capacitor aging and quality does come into play.

and for the most part it would work, If the units a decent brand and uses a SINGLE 12v rail id say screw it and go for it personally but i wont take chances like these on customers rigs or for rigs that are to last a number of years.

**The True Roman** · December 16, 2012, 10:25 PM

I have an XFX power supply, Not sure if its a good brand my friend recommended it after my other power supply crapped out on me. Its only about a year and a half old now.