Just installed GPU waterblock, Average FPS has halved and is a stuttery mess

[Turnip67]

Hi guys, I am at my wits end and i honestly don't know what to do. I would consider myself an advanced PC user but this has got me completely stumped. 

2 days ago i upgraded my GPU to liquid cooling with a Byksi water block for my gigabyte gaming oc 1080 ti (as EKWB don't make a block for this card). The build process all went smoothly. I booted her up yesterday, saw 22 degrees idle on the GPU die which made me very happy haha. I fired up some game benchmarks to put it through it's paces, and for the first hour or so all was running fine. It was running a few fps higher than when it was on air which is to be expected thanks to the higher boost clock enabled with lower temperatures. Then all of a sudden across every game it started to stutter and my fps halved. I was getting 110 fps in Rise of the tomb raider, which has now dropped to 60, same with many other games and also GPU benchmarks like Heaven.

I was running an overclock on the CPU, GPU and Ram at the time so i set everything back to default, reinstalled the latest nvidia drivers, and still nothing. I've tried disabling the xbox game thing in the registry, i have ran the gpu in debug mode from the Nvidia control panel with no improvement. It never did this whilst it was on air on the stock cooler and no hardware was changed expect for the addition of the GPU waterblock. 

I honestly don't understand what is happening. My CPU and GPU temps are fine. . Under full load, the GPU never gets above 40 degrees, the CPU never above 70. It has never crashed either, so it seems stable, my FPS has just halved. The only thought i had could be overheating VRMs, but none of the monitoring softwares (Aida64, GPU-Z or HWInfo show my GPU VRM temps and i am certain that i put the thermal pads on the right spot on the GPU. 

Any help would be greatly appreciated as i really have just spent a lot of money and seemingly ruined my system  

[RainfallWithin]

What is your GPU core clock speed when running a benchmark or stress test?

[LightskyTiger]

That's extremely strange, as Rain said, check your clocks while stressing and see if they are normal [For this problem, I doubt they will be.]

[Turnip67]

Thanks for the replies!! Sorry for the late response on this one guys as it has been working since the day after i posted this and so far is still fine... But to answer your question, the core clock was behaving normally, boosting up to 2050mhz or so when O'cd and under load, utilisation of the GPU was at 100%, vram usage was normal depending on the title. Power % was also normal around 100% or so when doing a benchmark. That is what i didn't understand, everything was behaving exactly as it should. What seemed to fix it, if you can believe it was just unplugging all the cable associated with the gpu and plugging them back in again....

I have absolutely no idea why that helped, but it has been working fine for a week so fingers crossed haha. If you have any thoughts as to why this might be feel free to let me know. 

Thanks!