Why is only one card working in SLI?

Status
Not open for further replies.

kaio37k

Distinguished
Apr 3, 2013
239
0
18,680
I recently got an EVGA GTX 660 Ti 3GB to pair with my PNY GTX 660 Ti 2GB so I can run them in SLI, but so far, only one of the cards works at a time.
Both cards work by themselves, I have an SLI bridge connected, but they won't work together.
I'm using RivaTuner from MSI Afterburner to get my readings and it says
GPU 1 Usage 0%
GPU 2 Uage %100
What is wrong?
 

md1032

Distinguished
Dec 31, 2007
297
0
18,860
First off, you've disobeyed the general rule found in the FAQ that you shouldn't mix two cards with different amounts of memory.

http://www.tomshardware.com/forum/245454-33-crossfire-faqs

I also found this thread that is relevant as it shows how you can get screwed by buying different graphics cards.

http://www.tomshardware.com/answers/id-1847525/set-sli-cards-memory-sizes.html

If I had to guess, it's a hardware incompatibility issue, but do one more thing for me. Go to the following screen in your Nvidia Control Panel and tell me if the SLI option is grayed out:

http://img.photobucket.com/albums/v451/MD1032/Other/NvidiaCP_SLI-2.jpg
http://img.photobucket.com/albums/v451/MD1032/Other/NvidiaCP_SLI-1.png

(Photobucket is acting up, try both links)

 

kaio37k

Distinguished
Apr 3, 2013
239
0
18,680


It's definitely not the games, I've tried ArmA 3, ArmA 2, Kerbal Space Program, Metro: Last Light and none of them 'activate' GPU 1. And I know that ArmA 3 and Metro support GTX 660 Ti SLI.
And wouldn't the cards automatically be run at the same speed? Or do I have to do that manually?
 

kaio37k

Distinguished
Apr 3, 2013
239
0
18,680


I know you should'nt buy two with different VRAM but when I bought it (used) he listed it as 2GB when in fact it was 3GB.
SLI is not greyed out, but that option is not visible. Here is a gallery of GPU-Z for GPU 1 & 2, and my Nvidia Control Panel: http://imgur.com/0wFVkPu,qutArRE,AXyuXZl
 

kaio37k

Distinguished
Apr 3, 2013
239
0
18,680


For some reason Tomshardware is acting up, not letting me reply and picked this as the best solution. The issue still has not been resolved.
 

kaio37k

Distinguished
Apr 3, 2013
239
0
18,680


Enabling SLI isn't an option.
 
I'm wondering if it might be because the 3GB card is a bit of an oddity, Nvidia spec the 660Ti as a 2GB card and a 4GB card would just be able to use half it's RAM but a 3GB card would have to use two thirds of it RAM and PC's don't like those kind of maths. That's just speculation though.
 

kaio37k

Distinguished
Apr 3, 2013
239
0
18,680


Anyway to test if this is the issue? I'm really open to any solutions.
 
Status
Not open for further replies.