Hoping someone can help me here.

[Heavenswake]

I recently purchased a 1440p monitor to use as my main monitor to go alongside my 1080p monitor and noticed I get very noticeable frame stutter/skip/hitch after gaming for a while. This stuttering immediately goes away if I unplug or disable my second monitor (1080p one). 1440p monitor is connected to dvi and 1080p monitor is conencted to hdmi (it only has hdmi).

My system is

4670k OCed to 4.4
Asus Maximus VI Hero RoG
8GB 1866 RAM
680 4GB EVGA FTW+
650w SuperNova Gold+

Stuff i have tried to get rid of the problem:
Memtest showed errors on RAM when I tested both sticks together, I am currently running on 1 stick that showed no errors after 9 hours/15 passes so this stick should be good
Disabled OC
Tried different video card, I had bought a 970 thinking that was the problem so I sent it back but the problem is still showing up on my 680
Disabled aero
Both monitors are running 60hz
I tried running my second monitor off integrated gpu but it still stuttered after a while
Bought a new dvi cord
Tried different slots on the gpu
Set power options to prefer max performance



As it's going my second monitor is going to turn into a paper weight unless I can get this figured out.

[Korth]

NVidia does support multi-display, but configuration will be a pain if (up to three) monitors aren't identical resolutions.

Also, you're basically pushing 4K worth of pixels from a single GTX 680. It's just not quite macho enough when tasked with heavy video playback/decoding or peak 3D render/physics sorts of stuff at that combined resolution.

If you're only running 4GB or 8GB of main RAM then things will bottleneck whenever 4K worth of texture data needs to be shuffled to and from the 2GB VRAM on your GPU. The GPU frame buffer needs to cache data in main RAM whenever it isn't large enough to hold everything it needs - not enough RAM can mean slowdowns and stutters (especially if it needs to extend a virtual cache to much slower NVRAM SSD storage or horribly glacial magnetic HDD storage).

You can try running all your RAM (both the good and bad sticks) at a lower JEDEC, say DDR3-1333 or DDR3-1600. If your bad stick still fails at slowest compatible speed then just toss it (but keep the heatspreader, if you like). Maybe try it in another mobo first. Maybe try using an electrical contact cleaner on it first. You've already done everything else I would recommend, aside perhaps from a clean OS and driver reinstall.

The GTX 970 should have been a mighty upgrade. But what you really need is more RAM. I would purchase a DIMM pair identical to your existing (4GB or 8GB?) working one, or even remove all your existing memory and upgrade to a 4x4GB DDR3 kit. You may still see better performance when driving your second monitor from the integrated GPU.

[Heavenswake]

https://www.youtube.com/watch?v=q1WvPRB_p1g&feature=youtu.be when I run by the fountain in the begining of the video you can notice it being jumpy/jittery despite being at 60 FPS, low FPS is not the issue or losing FPS. Just the fact that things don't appear to be smooth. VRAM usage is 1.5GB out of 4 GB, GPU usage is around 40% in that video. Everything looks to be working as normal nor is my fps fluctuating, but I'm the animations aren't smooth.

[Heavenswake]

Oh yeah forgot to mention I also reformatted. Another thing I forgot to note is the stuttering occurs even at a solid 60 FPS. My 680 also has 4GB of VRAM, as well as the 970 I had the issue with before this. I can try lowering the RAM setting and see if that does anything and I only tried the integrated GPU to see if having a difference source for my second monitor would change the stuttering. It's just weird when it happens I am still getting 60 FPS and my GPU load isn't even above 60%, nor is my CPU load. Also it's not like my game has gotten more demanding all of a sudden, I can be sitting in one area and run circles then it will sudden start acting up.

[Korth]

You could get by with 4GB (technically even as little as 2GB) of main RAM. But anything less than 8GB will hurt your fps, I think. If you have 16GB then you can use the ROG RAMDisk software to basically force all the graphical texture data to stay resident (one way or another) in physical RAM to help ensure consistently high fps.

[Heavenswake]

Yes I run vsync which is why it's capped at 60, without it the stuttering is far worse and is also accompanied by screen tearing.

[Korth]

Are you using V-Sync? Maybe even G-Sync? They both address this specific problem.

Obviously there's more 3D objects (and even a little physics) involved in drawing that fountain than on the other onscreen objects in that environment. Agreed, your GTX 680 should be more than enough for the task, unless you're pushing huge resolution. I'm still of the opinion that more RAM should improve overall performance, although perhaps not in this specific instance.

Sorry, can't think of anything else which might be helpful.

[Heavenswake]

I'm not sure if it's related, but I also get these weird GPU usage drops. You can see frame time spikes before and after, then the usage returns to normal. I'm at a loss for what is causing the stuttering and I don't know how to check my mobo/cpu for problems.

[Korth]

Is this consistent with other games? Can you ask for any nearby players to report their fps observations?

It could just be bad game code. Blizzard has been known to release the odd bug now and then, lol.