Date: Saturday , August 05, 2017
Below is a picture of our first test fitting. We used a Thermaltake Floe Riing 360 AIO, which of course uses an Asetek coldplate.
Back when Ryzen was introduced we found that the heatspreaders on these CPUs were extremely flat, which is a good thing, but not when your waterblock is fairly convex shaped. We found that we needed to lap those older AMD blocks to get a good mating surface for cooling. We did address this in our AMD Wraith Cooler coverage as well.
Continuing our Threadripper testing this morning, I pulled the cooling system in order to check our mating between CPU and AIO.
I think we can all agree, that is a horrible mate. Some of this might be on me for using a bit to much TIM, but a few more mountings will tell the tale. I am not a big fan of this type of holddown bracket used by Asetek, but going back with a straight edge razor, it is fairly obvious that while the Threadripper IHS is about as flat as possible, the Asetek coldplate is not. The Asetek mating surface is convex. You can lay a razor across the middle and see that it only makes contact in the middle.
Considering the huge size of the Threadripper IHS, you need to be getting as much contact as possible from your cooing system's coldpate.
Looks like we have some sandpaper in our future.
So getting the AIO out in the garage and getting it lapped did happen, but it was not without its issues. The coldpate is so small that it is extremely hard to get a good hold onto, then with the very stiff tubing attached to it, I could only get it so "flat." It is a lot better than it was, but certainly not close to a true flat.
Much better but extremely far from good. I simply do not like these types of AIO mounting brackets. They are cheap and do not distribute pressure evenly. And keep in mind this is being extremely careful during install on an open test bench. Trying to do this inside a case would be extremely difficult.
After our lapping and our second install, I let the system run for a while and got some heat through. I applied the TIM to the coldplate and after getting a nice smooth and very thin coating, I laid a dab down in the middle hoping to get some flow to where it was needed and this seemed to work out very well. I installed the cooler with the unit laid flat on the test bench. Once I got a few threads on the mounting bracket, I inserted the cooler and held it down firmly in place while going around tightening down on the screws in an X pattern. I am much more happy with this result.
So spending some more of the day with just focusing on how to get the best mount on this cooler, I finally hit the grail, albeit somewhat unholy. I do not think there is any way I could have gotten this good of a mate between the AIO and Threadripper without lapping this coldplate a bit.
I am calling this mounting a huge win compared to where we started out at the top of this page. This is by far the best mate, out of the 7 or 8 mounts I have done with this system.
This was the process I used to get this mate. I first installed the mounting bracket on the TR4 socket, but I only let the screws get less than one full thread grab. Then I laid down a very thin layer of TIM all the way out to where the inner edges of where the screw heads are exposed. I figure having this thin layer even at the edge will facilitate easier flow of the TIM material under pressure. Then I laid a significant "blob" dead in the middle approximately the size of 3 grains of rice. I then carefully inserted the cooler into the bracket, making sure NOT to press the coldplate down onto the Threadripper CPU. I turned the cooler head till it locked into the "teeth" on the mounting bracket (Getting these set exactly right is important). Instead of pushing the coldplate down onto the CPU as I have done previously, I kept force pulling the coldplate up against the mounting bracket. From there I tightened down in an X pattern, with no more than one full turn on the screw at a time. (Yeah, this is a bit tedious, but be patient.) I tightened down till all four screws bottomed out in the mounts, which should happen on the same pass if you counted your thread turns correctly.
Your mileage may vary, but if nothing else, I hope this points out using these Asetek manufactured AIO coolers is not just a "point and shoot" operation. Take your time, be patient. I also do not see this technique to be easily done inside a case with the motherboard already mounted. I did mine on solid test bench surface where I had plenty of room to work.
For the sake of discussion, here is AMD's suggested TIM application for Threadripper.