Can I run GTX 680 2GB and 4GB in sli?

JB00Junior

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Feb 27, 2012
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Hi Guys

So I recently just treated myself to a new gaming rig:

Chassis: CM HAF 922
CPU: i7 3930K
PSU: XFX 1050 watt black edition 80+ Gold
MOBO: Asus X79 Deluxe
GPU: 2x EVGA GTX 680 SC Signature 2GB running in SLI
RAM: 2x Kingston Hyper X 8GB 1600 kit
HD's: PATRIOT PYRO 60GB SATA 3, and 2.5" SEAGATE 1TB 7200RPM
DVD ROM and will get Blu Ray on pay day.

I've just read a forum on the GTX 680 2GB VS the GTX 680 4GB as to which is more future proof. Some people feel the 2GB isn't enough vram for future games, as some games like metro 2033 allready uses like 1.9 gb vram, thus making the 2GB card less future proof than the 4GB version.

My whole idea was to buy a gaming system that will take at least 3 - 5 years befor I need to make major upgrades to cope with the latest games of that time. However, when I bought my rig a few weeks ago, the 4gb version wasn't available in my country, (South Africa) so I got the 2GB version thinking that is more that enough. It will annoy the heck out of me if a powerful card like the 680 might suffer due to a lack of enough vram with later and more demanding games.

My questions are, can I run, say another evga gtx 680 4gb card with my other two gtx 680 2gb cards in 3 way sli? and then just use the 4gb one as the dedicated gpu or what ever they call it? Also, is my PSU big enough to handle 3 way sli? CPU bottleneck with 3 way sli?

PS, I'm using a 27 inch Samsung S27A950D 3D monitor. I play my games at 1080P and in 3D.

Thanx guys
 
First of all, according to what I've researched including comments from EVGA engineers that tweak reference designs, there is not as much difference today between 2GB and 4GB of VRAM when it comes to raw performance with the Nvidia cards. Much of it has to do with the newer memory architecture. You may get some benefit from going 8xAA over 4xAA in a handful of games, but I have yet to see any benchmarks showing the 4GB card - at any resolution including 5760x1080 - being worth the higher price. And that's not likely to change any time soon.

Regarding 3-way SLI, you can run both cards of different memory, but the extra 2GB of that 4GB card will not be used. I assume you mean run that third card for PhysX, which should be installed as a stand-alone card (not SLI'd). That would be an enormous waste of money. Finally, you need to check your PS for the 12v rail output to find out if it's good enough to meet the demand for three 680s (again, a waste of money IMO).
 

JB00Junior

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Feb 27, 2012
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Thanks, but that doesn't really answer my question of sli'ing a 4 gb with a 2gb

 

JB00Junior

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Feb 27, 2012
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10,510


Thanx man, guess I'll just stick with my two 2gb cards and suffer the bit lower fps in those very demanding games. :(
 

EchoOne

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Jun 24, 2012
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You can run it with no problems...Gah people you can run any cards as long as they are the same...No problems..Im running 6870's 1 1gb and another as the 2gb..If you get the 4gb put thaat one on the very top PCI express slot..

EchoOne