Question GTX 1080ti running very hot

Sep 23, 2021
First time PC builder here,

I owned a Corsair One Elite, 2 weeks ago the CPU cooler on it broke. I spoke to corsair and long story short they were unable to help. So began the process of fixing it. The corsair one's radiator is not standard and a replacement water cooler AIO wouldn't have fit. So I began the process of ripping everything out of the corsair one unit and rebuilding it in a new case.

The rebuild has gone well with one exception. Transferring my graphics card has been difficult. I have a GTX 1080 ti water cooled. The radiator for the GPU is the same as the CPU's, so it wouldn't fit in the new case. I attempted to get a second copy of the replacement AIO cooler I got for the CPU (Corsair h100x). Though the h100x didn't make proper contact with the GPU and wasn't cooling GPU. I was then told by some friends that a CPU cooler isn't powerful enough to cool a GPU. To fix this I went back to the old GPU cooler I had in the corsair one case and after zip tying the h100x fans to the radiator (the radiators dimensions were weird so it didn't line up for screws) I was able to get the computer running at stable temps. However, having a radiator hanging out of the case (the tube's weren't long enough to mount it anywhere) wasn't going to be a long term option.

I began the process of trying to figure how to replace the tubes and radiator. After watching some youtube videos and reading forum posts about AIO modding I began the process. The old pipes were about 6mm inner diameter (~1/4") but I was unable to find pipes smaller than 10mm (~3/8"). I was able to wrap plumbers tape around the prongs to make the tubing fit, secured it with hose clamps and both prongs are water tight. I successfully filled up the new cooling parts with liquid and had only a few small bubbles in the tubes (I was told a few air bubbles is fine). However, when I run games on my computer the GPU is hitting 70-82 °C (I'm pretty sure thermal throttling kicks in around 80°C). Before hand it was running no higher than 60°C.

I don't believe the pump has been busted, as the refill process was smooth and no strange noises come from it. The radiator is being properly cooled, fans running, outtake tube cold, intake tube warm. Coolant is about 10°C cooler than the GPU. All seems to working fine, but I'm still having temp issues. My only hunch is that by increasing the tube size (~4mm) and increasing the lengths of each tubes (22mm --> 44mm) that their is more coolant than the pump is use to, and it is not pumping hard enough to adjust to the new volume. I took it off and tested the flow (video linked), it seemed very low to me, but I'm not sure as this is my first time. This is my last ditch attempt to try to get some advice on how to proceed as I'm trying to avoid spending the ~$2,000 for a new graphics card. I'll have some photos below.

The GPU cooling pump/radiator isn't a stock part and doesn't have a part number, the pre-build computer is a corsair one elite CS-9000014

Thanks in advance, any help is appreciated.


CPU: Intel Core i7 (8th Gen) 8700K / 3.7 GHz

GPU: NVIDIA GeForce GTX 1080 Ti

RAM: Corsair DDR4 2 x 16 GB 2666MHZ


Old radiator with zip tied fans


New pipes and radiator in the case


Flow video

hmm im running 1070ti with cpu aio cooler 480mm rad and with modded power ...performs as 1080 (non ti) and it doesnt goes above 50C
so that person who said that cpu cooler is bad for gpu doesnt know what hes talking about

point of watercooling is to take heat away fast from gpu to radiator...your video shows that you get no flow at should be aiming for 6liters/minute