Wait, this is the exact same shit I've gone through the past week. A bit more details…
Timeline
NH-D15 (with contact frame,
working CPU) -> Freezer III (
BENT CPU, no dual channel working) -> Freezer II (with contact frame,
new CPU, sadly a damaged pump) -> Freezer III (
BENT CPU again, it's working tho)
I have installed several cooling solutions and built many PCs over the past 20 years, but this shit is something else. And after a whole new CPU, I also think I know why this is happening. It all comes down to the terrible contact frame from Arctic. If you move the frame towards the yellow arrow in the picture, and then start with the top screws first, you will bend the CPU within the red outline. It's enough to bend the CPU that it will not start with dual-channel, or simply not boot at all anymore. I've gone through intensive testing why my ram was not detected anymore.
I would take a picture from my new CPU that I've installed, but I won't remove that shit until I really have to or replacement is here.
View attachment 342053
I didn't immediately see the bending of the first CPU after I've installed the Freezer III. My initial thought were focused on other things, as CPU's rarely get damaged and it never happend to me. As only dual channel was not working anymore, I've ordered a new Motherboard and GDDR5 RAM. Installed both and the same error came up, it was stuck at RAM while booting. Sometimes it would get stuck with a red indicator at CPU, so I've decided to really take a deep look at what the fuck was happening. Took the CPU out again and saw that it was clearly bend at the bottom part. Well... now I knew what was causing the issue.
Ordered a new CPU, came within a day and installed it with an also new Arctic Freezer II, everything was working great, but the Pump was sadly insanely loud and I could not fix it. It was more of a rattling and not some air bubbles. I used the old contact frame with the Freezer II and after removing everything to get my Arctic Freezer III again installed, I've made sure to look at the CPU and there was nothing, no bending, no damage at all.
Now today I've installed the Freezer III and was immediately greeted with a red CPU indicator and once again sometimes it was flashing Red and Yellow for both CPU and RAM. Took the thing apart once again to see what is the issue now, and I obviously looked for the CPU again, and it was once again bent at the same point. Now I was messing around with the contact frame a bit more and played with it, there is clearly something wrong with that thing. Why does it have the bottom open that much, so much that you can actually move the frame quite a bit and install it in almost two positions? One position holds the CPU more centered and one which is like in the picture more towards the top of the frame. I took the frame and pushed the CPU completely against the top of it, installing the bottom screws first because the CPU is bent there so it needs contact. And suddenly the PC started, with dual-channel enabled, etc.
I'm not 100% sure this is how the bending really happened, that's a theory of mine. I've spent a whole week troubleshooting wild things, but all I know is that there is something very wrong with the mounting. Furthermore, I'm currently debating on sending the Freezer III back, but that would also mean that the potential damage could be much bigger just from de-mounting again, resulting in the loss of the CPU once again. What a week this was...
Hey.. but at least the Freezer III has no pump issues for my part, it's really quiet.