I swear I must have the worst luck with computers, the problems never stop :'( 

I upgraded from an old 1080P 60hz monitor to an ASUS pg279q 1440P 144hz Gsync monitor about a month ago. I was always wondering why I basically didn't notice any difference between 100+ FPS Gsync and 60 FPS Vsync (apart from input lag)
Now, I seem to know why. I get an odd micro stutter when I move my mouse around and look around. Makes gameplay look stuttery and not smooth. Even if I maintain a high 100+ FPS with a steady GPU usage and no drops. This seems to happen regardless of what FPS I have.
I've tried GSync On, Vsync off/on, as well as just setting the refresh rate to a fixed 60 and using Vsync. Some games seem to stutter more than others, Rainbow Six Siege being the worse, followed by BF4 and BF1. Battlefront... surprisingly I don't notice any.

I remember before when I used my 1080P 60hz monitor, I got lots of stuttering on top of screen tearing with Vsync off. I know screen tearing is normal, but stuttering... really shouldn't be. 
I've tried messing with the mouse polling rate as well as sensitivity in game and DPI in settings. Nothing seems to really help.

I'm fairly certain its not the graphics card. I had the same issue with my 1080P monitor before when I ran a GTX 1070, now im on a GTX 1080 with a 1440P monitor and I'm experiencing similar stuttering issues. (Tried the 1080P monitor, same issue)
Sad to say that 1080P 60hz Vsync on, performs better if not around the same as 100-144 FPS Gsync 1440P in my situation.

I've already reinstalled the OS a few times. I'm fairly certain I'm not doing anything wrong in terms of install. I really barely install anything. I always turn off fastboot, wipe the drive and all partitions, then install all the chipset and what not drivers. Then install basic stuff like office, chrome, firefox, afterburner, steam, origin, HWmonitor, etc. Then my games. 

I've been suspecting somethings wrong with my motherboard, Its getting replaced regardless. I know a malfunctioning motherboard can cause attached hardware components to not work well. Can one of the symptoms of a possible motherboard malfunction include what I'm experiencing?

Thanks for the help guys! 

wmmills
What mouse are you using? Are you using its driver or windows default driver? What games does this happen with? What drive has the os, which has the games and do you have the pageing file on? How filled is each drive? What windows are you using? What ISP do you use and what tier?

Logitech G402. I've downloaded the latest firmware and I've been using the Logitech Gaming software. So it should be their drivers.
Happens in Rainbow 6 Siege, BF4, BF1 (Haven't tested on any other games) Battlefront doesn't suffer from it much. OS is on a Samsung 850 EVO 250GB, games are on the same drive. Stuttering has happened when its just been the operating system and one or two games with 100GB or so of extra space.
Pagefile I have set to automatic, its around 2.4GB and is also on the OS drive. 
Windows 10 Home, latest build/ version.
ISP: Centurylink Ethernet connection ~21MB/S (This happens to an extent on singleplayer as well, so its not internet) 

Thanks for the reply! I've suspected the mouse as well. Im going to see if any of my friends have a better mouse I can try out. I tried a stock Dell potato of a mouse, and the stuttering got extremely worse. So... maybe theres a connection.

Wooohah

wmmills
What mouse are you using? Are you using its driver or windows default driver? What games does this happen with? What drive has the os, which has the games and do you have the pageing file on? How filled is each drive? What windows are you using? What ISP do you use and what tier?

Logitech G402. I've downloaded the latest firmware and I've been using the Logitech Gaming software. So it should be their drivers.
Happens in Rainbow 6 Siege, BF4, BF1. OS is on a Samsung 850 EVO 250GB, games are on the same drive. Stuttering has happened when its just been the operating system and one or two games with 100GB or so of extra space.
Pagefile I have set to automatic, its around 2.4GB and is also on the OS drive. 
Windows 10 Home, latest build/ version.
ISP: Centurylink Ethernet connection ~21MB/S (This happens to an extent on singleplayer as well, so its not internet) 

Thanks for the reply! I've suspected the mouse as well. Im going to see if any of my friends have a better mouse I can try out. I tried a stock Dell potato of a mouse, and the stuttering got extremely worse. So... maybe theres a connection.

Yeah, I would dump the Logitech drivers first thing then reboot and try. As far as the games go they are more cpu dependent games, are you overclocking the cpu? the reason I ask is because if your vcore is too low, say by a tick, youll boot and run but in games and heavy work youll get that weird stutter but few if any crashing, so raising it a tick may be option also. In the NVidia control center do you have the physics setting on auto detect? If it was me and I truly wanted to find the problem I would dump windows 10 and revert to 7 if all else failed, but I understand if that's not a option for you.
You do have to run vsync and gync both at the same time from what ive seen other say about it, is that what your doing? I got the impression that your separating them while testing.

Wooohah
I'll try removing the logitech drivers and try again. But I believe I didn't start installing drivers for the logitech mouse until recently, and i've had this problem for as long as ive had this computer.

I am not overclocking the CPU, CPU usage stays around 50-75%ish depending on which game and is for the most part pretty steady. 
I have BIOS running on default settings, so VCORE is automatic by the ASUS board. I have a max performance setting on, so VCORE is at like 1.360V. So voltage should be ok

Ill have to check on the Physics setting... I dont believe ive touched anything related to physics.


unfortunately going back to 7 is not an option, I've learned to do a lot of my troubleshooting on the Windows 10 OS, going back to 7 may prove difficult if I run into problems again. I installed Win 7 on my old backup PC and its a bit different haha, haven't used it in 2 years. 

I saw a previous thread you had about this sort of and sajin solved with the polling rate for the mouse, I guess it was interfering?!!? So yeah, maybe removing the Logitech software and going default windows mouse drivers may help or different type of mouse. Maybe try a laser mouse instead of a optical, if that's a available to you. You do have windows update shut down right? that thing will go off constantly and suck up all your cpu resources giving you the same kind of issues. It could just be another windows process, have you checked the task manager when a game is up, or not even, to see if anything is sucking down resources other than the game? 

I don't have Windows updates off, but I've monitored usage and there's nothing sucking up resources in the background. I've run it with just the game and Afterburner, all the usage looks fine. Windows updates arent running either. After a clean install I always leave the PC on overnight and it finishes all the updates 
 

Absolutely :) Tons of extremely helpful people on this forum. I've just been having really bad luck with this build and computers in general recently. Lots of my problems are just weird.... 

I'll try the mouse for sure and report back! I'm probably gonna see if I can pick up a different mouse to try.
I have performance set on max everywhere as well. I leave max pre rendered frames alone since I haven't seen a difference actually. But I should try 3 or 4 globally? 

I guess anything is possible, but if your system is stable more likely an adjustment / setup issue
 
You should run benchmark software and Not games to test for stability.
 
You talk of reinstall Win 10 - clean install ?
 
You turn Xbox DVR Off ? (MS turns it on by default in Win 10 1607)

This issue sounds game settings related to me. How does rainbow six siege play when you restore all its in-game graphic settings to default settings?

Video is super potato, I apologize.

Its a bit exaggerated in this video because of the low quality, but you get the idea. Panning/ moving around is not smooth, feels stuttery. I'm getting 95-100 FPS, Ultra with Gsync on in this video, yet it honestly feels like 50-60.
1080P 60hz Vsync on feels smoother than 1440p 144hz Gsync on...

Not sure why this is happening, Frames are steady and I'm not getting drops. I originally thought this was just Battlefield 1 since the only other game I had installed was Battlefront (which did not stutter) but installed BF4 and Rainbow 6 and amazingly enough, both stuttered worse than this.
Its almost like the higher the FPS, the worse the stuttering is almost. 

https://www.youtube.com/watch?v=MUD_opuWGbE
 

That's my normal setup, Gsync and Vsync enabled in Nvidia control panel global settings, Vsync off in game. I've tried Gsync on and Vsync off globally, same result for the most part 

I don't know if you read any of this info before, but you may want to try a 2000hz polling rate, if possible, is wha they came up with for gsync guys with 144 monitors. 1000 seems to smooth it out a lot but 2000 seems to fix it almost apparently. Windows 8.1 actually needed a patch to fix this so you might have a combo of things coming together to make this problem
.
http://www.blurbusters.com/faq/mouse-guide/

Turning off smartscreen didn't help :(

Tried my friends G502, no difference at all :( I suppose ill try and see if I can overclock a different mouse. Although it'd be sad if I couldn't use my logitech

What the best way to test my internet? I'm looking into this a bit more and it seems like stuttering is the most noticeable in Multiplayer games.
Minecraft out of all things even stutters in Multiplayer, however singleplayer is rather smooth. 

Ping is low, Wired connection, 21mb/s speeds, but I do get a high RS FEC correction rate showing within my Modem config.

No, stuttering is not really present in Singleplayer games, it seems like its more of a problem with Multiplayer games.
Minecraft for example was smooth in single player, logged into a multiplayer server and it was rather choppy.
Battlefield 4 was pretty smooth in Singleplayer, Multiplayer had a lot of stutter
Battlefield 1 I still need to re-test but It seems like its not really a problem in singleplayer but more a problem in Multiplayer.
Rainbow six, ive only tried multiplayer so far, I'd have to try an offline mode.

Battlefront does not exhibit any of the stuttering in neither singleplayer or multiplayer. However oddly enough BF1/4 both use the same Frostbite Engine.