Two monitors - two GPUs vs single GPU

[jander22]

I need some expert advice from someone who is intimately familiar with how graphics cards work

I have an EVGA 780 Ti Classified and I can run 2 monitors off of it without any problems, however I was wondering if there are advantages in dedicating the 780 to one of the monitors (for gaming) while running the second monitor off of the onboard Intel video adapter.
I know it can be done, at least in my environment (Windows 8.1 Pro); my question is not if I can do it, but rather should I?
Here are my questions:
1) If I DO run two monitors on two adapters, can I run a game in full screen (not windowed fullscreen) mode on my 780 on one monitor and still be able to move my mouse over to the other monitor?
2) Clearly the 780 Ti is fast enough to power multiple monitors and doesn't really break a sweat even in some of the more demanding game sequences; would it still benefit from running on a single monitor?
I use the second screen to monitor my GPU / CPU and resources and sometimes to stream video via Slingbox - more like background noise, while I play a game.
I know games run better (and can use Vsync) in full screen mode because the game then has full control over the frame rates, etc. I am not sure what happens when you run 2 monitors with multiple frame rate requirements on the same card, even though the game is in fullscreen mode. Since I have the onboard video readily available, I thought I would eliminate the possibility of the GPU being confused (or maybe thrown off) by multiple frame rate requests simultaneously.
I hope I explained my dilemma well enough to get a good advice, but I can certainly provide more information if necessary.
Here is my setup:
CPU: i5 4670k OC'd @ 4.3 Ghz
GPU: EVGA GeForce 780 Ti Classified w/ACX cooler OC'd @ 1255 Mhz
MB: MSI Z87-GD65
PSU: Corsair 750W Bronze Certified
RAM: 16 GB DDR3-1866
HDD: Samsung EVO SSD 500 GB (primary) and 1 GB WD Blue series for storage (documents, pictures, downloads, etc)

Games Played: SWTOR, LOTRo, AC4BF

 

[ronintexas]

Your card is plenty big enough to run two monitors without any issues....I would connect them both to the GPU.

 

[jander22]

I know I can, I am running two monitors on it now; my question was a little more complex than that and was looking for more factual differences, subtle as they may be... Thanks for your reply anyway.
Anyone else?

 

[ubertome]

I can't tell you performance/benchmark numbers of running one monitor off of a GTX 780 Ti and the other with integrated graphics, but I can tell you that it would be a comepletely pointless endeavor. Like you said, your card is more than fast enough to power 2 monitors, and is orders of magnitude faster than Intel's solution.

However, it is possible to run fullscreen on only one monitor on one video card: http://www.youtube.com/watch?v=hqqZlAlM0AI

Apparently there is an app that allows you to seamlessly transition between monitors called Actual Multiple Monitors.

 

[jander22]

I can't tell you performance/benchmark numbers of running one monitor off of a GTX 780 Ti and the other with integrated graphics, but I can tell you that it would be a comepletely pointless endeavor. Like you said, your card is more than fast enough to power 2 monitors, and is orders of magnitude faster than Intel's solution.

However, it is possible to run fullscreen on only one monitor on one video card: http://www.youtube.com/watch?v=hqqZlAlM0AI

Apparently there is an app that allows you to seamlessly transition between monitors called Actual Multiple Monitors.

Thanks for suggesting Actual Multiple Monitors. It does work in one game but not in another one. I may have to play with different key assignments but it's a neat program.
Regarding my initial questions - I am actually having some problems with FPS in games. I noticed that games start fine and I have a lot of FPS but shortly after FPS drops. Meanwhile, the GPU slows down (from 1200+ Mhz down to around 550-600 Mhz) while GPU load % increases to 99%. It doesn't seem to push itself to run at maximum performance, despite the fact that I changed power management to "prefer maximum performance" and "single display performance" in NVidia Control Panel -> Manage 3D Settings. I have a ticket open with EVGA to fix this issue. It's strange because I never had this problem with my previous card, a 660 Ti SC+
I'll call EVGA and see if they can guide me through configuring 3D settings for best performance...

 

[ubertome]

Assuming there isn't a more serious issue with the card itself, it sounds like it could be a heat problem. Perhaps you should relax the clockspeeds and/or make sure there's enough airflow in your case, since the 780 Ti is a pretty big card.

 

[jander22]

This card has the ACX cooler on it (dual fans), it is huge but it seems to handle heat much better than stock fan. It never goes over 55-60 degrees in games. Sometimes I see it go up to 75 during heavy stressing (benchmark tests) but other than that it stays pretty cool. CPU is at around 60-65 degrees under very heavy load (CPU stress test) but normally it idles around 40-43 and lingers around 50 during games (I am using a Cooler Master EVO series heatsink / fan). I have a total of 5 fans in the case, airflow is measured at 34 degrees.
Drivers may be an issue. EVGA tech suggested installing a previous driver. I will uninstall current drivers and install older ones to see how it behaves.
I do think you're on to something though regarding clocking - I ran a game at stock speeds and, while the frequency fluctuates, it does go back up when needed. It's still reactive as opposed to proactive, in that it sits at lower frequency while FPS drops and then it picks up to bring power back up. I had adaptive Vsync on per EVGA's suggestion but I will turn that off and see if it forces the GPU to go full speed... I'll keep you posted. Thanks for all your help.

 

[jander22]

Uninstalled newest drivers and installed previous version. Down-clocked the frequency by 10 Mhz to 1235, seems stable. 3DMark and Heaven run fine, GPU gets a workout at full throttle. Games are decent, although I still have FPS fluctuations and the card seems a bit too "relaxed" for my taste, but it is definitely better than before. SWTOR must have an FPS cap, I am constantly at 100 with occasional dips. LOTRo - different story, but that game has it's own lag issues that can't be optimized much beyond a certain point from a user perspective (FPS fluctuates between 35-350)

This card is definitely a monster though, it can handle much more than I use it for. The only reason I went from a 660Ti to the 780 Ti Classified is to support the new GSync 27" monitor at 1556x1440 which I am thinking of getting when it comes out (Asus). Right now I'm running dual 24" @ 1080p but only game on one of them.

Back to the main topic - I did run some tests with monitors connected to different video adapters. Benchmark tests came back the same, slightly higher when second monitor was connected to Intel's onboard adapter, but only by insignificant amounts - Heaven benchmark scored 2179 (86.5 FPS) when both monitors were connected to the 780 and 2186 (86.8 FPS) when the second monitor was connected to Intel adapter. Again, this doesn't mean anything as the difference is insignificant and can be attributed to many factors; the fluctuation is within normal, expected range.