Low end GPU and 680 SLI

[BrightCandle]

Many months ago I found a bug with 680 SLI and 120hz monitors. In essence when I add a second monitor performance in windows degrades dramatically as if the underlying frame rate is below 30 fps. I reported it to NVidia but I haven't seen any progress. Thus I doubt they are trying to fix it.

So with that in mind I really do want to add back a second monitor without loosing the 120hz Benq screen. Does anyone know what would happen if I added a very low end NVidia/AMD card to the machine and put an additional monitor on that? Would it conflict with SLI perhaps or might the cause of this bug lay in Windows?! I am unsure if I can get a second screen working in this way. Has anyone ever done it?

 

[stahlhart]

Have you checked with Mark Rejhon...?

 

[xeledon20005]

not really sure what you mean i have a single 4gb 680, using the 144hz monitor from asus with lightboost. With that backstory i can tell you my first screen is 1920x1080, and my second screen is just a 1680x1050- normally have that monitor off its only 60hz. I don't have any problems with first navigation or anything, but if i move a window over to the other monitor and move the window a bit there is a bit of tearing/stutter not sure. Should this be happening I mean ive got 4gb of video memory it should be able to support multiple displays easy.

 

[BUnit1701]

It would seem the OPs issue stems from SLi.

@ OP: You should be fine adding a low end card to drive your second monitor. To save driver headaches, you should probably go with an Nvidia card.

 

[BrightCandle]

I am pretty certain the problem is with SLI. If I turn SLI off the problem is reduced, but I have also found out that SLI doesn't really ever turn off. I would remove a card to test and confirm its SLI but due to the watercooling it will take me about 2 days to do the test and get my SLI back up and running. Draining a loop and pulling it apart is not a fun activity that I do on a hunch that the problem is most likely only showing up under SLI. I certainly reported the bug initially as an SLI problem.

 

[moonbogg]

Can I add a 3rd graphics card in my 2-way SLI enabled PC to connect more monitors?

Yes, you can add an additional graphics card to your PC to connect two additional monitors. The additional graphics card must have a GPU that is different from your SLI GPUs and must be NVIDIA PhysX capable (GeForce 8 series and higher with at least 256MB of memory). For example, two GeForce GTX 2XX GPUs in SLI and a GeForce 9XXX GT is a supported configuration.


From Nvidia website.

EDIT: This does not speak of different monitors with different refresh rates though. In theory, the separate GPU could output its own 60HZ signal while the SLI cards output their own 120hz signal, but if the driver doesn't do this then you will still have tearing issues etc. I give it a 75% chance of working. GO BUY IT and report back! (or borrow a cheap card to test)