I have a massive performance drop when I enable SLI (Core I5 650 and GTX760 SLI)

[deanesterhuizen]

Hi guys

Just installed 2nd GPU (for SLI)

I have a massive performance drop when I enable SLI (maximize 3d performance) in Nvidia control panel.
After I enable it and run 3dMark (Firestrike) it drops to 10 frames vs. 30 frames without SLI enabled. (doing just the fist test)

Is my CPU the problem?

- Intel® Core™ i5-650 Processor (4M Cache, 3.20 GHz)GA-P55A-UD4P
- 8 GB RAM
- GA-P55A-UD4P
- 2 x GIGABYTE nVidia GeForce GTX760 OC - 4096MB GDDR5, 256-Bit Memory Bus, PCI Express 3.0 – SLI
- Cooler Master GXII 650W

 

[pyr0_m4n]

For SLI, yeah that looks like a bottleneck especially since that only is a dual core.

 

[Zalastair Clark]

Your power supply isnt big enough if you have any overclocking done. The 2 graphics cards can use up to 400 watts overclocked. Leaving you with only 250 for mobo hard drives fans processor and ram

 

[Mousemonkey]

Your power supply isnt big enough if you have any overclocking done. The 2 graphics cards can use up to 400 watts overclocked. Leaving you with only 250 for mobo hard drives fans processor and ram

They are only 170w cards and as I have had SLi'd 170w cards running on a 620w PSU I would have to disagree with you on that.

 

[anthony8989]

Definitely not the PSU. If you had insufficient power to a component, the PC would BSoD or just shut down. Almost definitely your CPU is bottlenecking your system. If you are limited in funds I'd recommend taking one of the 760's back and getting a new mobo + latest gen i3-4xxx or an I5-4xxx if you can muster a little more cash.

 

[anthony8989]

Oh wait a tick - your PSU only has 2 x PCI-e connectors at 2+6 , how did you provide power to both 760's? They each need 6 + 8 PCI-e connectors.