H115i Cooling problems, possibly contact related

I installed an H115i on my Asus ROG Strix Z390-E motherboard and am having no end of problems. My 9900k is idling at 40C and is spiking to 80C just on windows desktop (with no overclock).

 

I've removed and reseated the waterblock with fresh TIM each time and it's made no difference, I've removed and reattached the backplate but that's not helping either.

 

From looking at the TIM each time it appears that the block isn't fitting flush to the CPU when the screws are tightened. I've tightened them all evenly and as tight as they'll go but the issue persists. It's almost like the backplate side of the standoff doesn't have enough thread to pull the backplate tight. I'm using the correct standoffs for the socket.

 

Any ideas what could be causing this, the pump is running and the water temp is 24 degrees so it's not a pump issue.

I would say you are almost certainly correct in your diagnosis and it appears to be a contact problem. Unfortunately, this tends to be a fiddly, motherboard specific affair and often only another owner can share specific knowledge. Aside from obvious mistakes (wrong bracket, stand-offs, etc.), the next most likely thing is probably back plate orientation. Some of them need to be turned a specific direction, despite appearing to be congruent.

 

Do you have the H115i, the H115i Pro, or the H115i Platinum? I believe all three have slightly different backplates.

I've got the H115i Platinum.

 

I'm convinced that the issue is the length of the prongs on the backplate. They stand proud of the motherboard surface so when you screw the standoff into it the face of the standoff meets the face of the backplate rather than the top of the motherboard. So when you screw the block onto the standoffs they pull away from the motherboard creating a gap (and thus not making contact with the CPU).

This is what my CPU and chiller look like.

 

https://1drv.ms/u/s!At5nfHhSG5X7g5g0_FZmc7aTO7rRww

 

https://1drv.ms/u/s!At5nfHhSG5X7g5gzepLKH77Gv3-Ffg

Yes, it looks like it might not be even pressure in the lower right corner. Unfortunately, the Platinum model is the one I don't have and the backplate is by a different OEM. Might need one of our Platinum owners to offer some insight on this.

HI!

I noticed the motherboard was to thin. So i used plastic washer to the backplate and the problem was no more :)

My mother board is Asus ROG Strix z390-F Gaming.

I suspect I'm going to need to do something drastic like that. I've put my H100 back on for now (it worked first time with no heat issues), but at 7 years old it's getting a bit long in the tooth.

Forgot to tell you i have also 9900k and H115i platinum..... Cooling works fine, but rgb an usb don´t....

Any idea how thick the washers you used were?

I'm now thinking that I'm using the wrong standoffs.

 

There are 3 sets of standoffs that came with the chiller, however the manual only mentions two types.

 

There are some short and even ones, some short ones with one short screw and one set of long standoffs. The picture in the manual looks like the longer set is for the LGA1151, but now I'm reading on other websites that there is a set of Threadripper standoffs included in the package, which standoffs are which?

 

Edit: I've found the picture of the TR standoffs in the manual (the short even ones). I'm using the long even ones so they appear to be the correct ones.

The washers i used is about 1-2mm thick.

I included a pic off my standoffs :)