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i7-5820k Overheating After Lapping

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New Member
Feb 12, 2021
So I decided to get adventurous and take some sandpaper to my CPU and AIO cold plate because I've never been happy with my temps. Started with 240 grit wetordry, finished with 2000 grit, on a piece of glass for flatness. The cold plate was remarkably even and didn't need lapping. The CPU IHS was convex and I took some material off. At first I thought the overheating was because water got into the small hole in the IHS and hadn't dried completely and was shorting something, but now I'm not sure. Here is the order of events so far:

- Lap CPU and cold plate

- Top off AIO with distilled water and cleaned out the gunk build-up in the coldplate's fins.

- Resocket and repaste with IC Diamond

- Replace GTX 1080 with RTX 3060 Ti

- Turn on computer and update Nvidia drivers first thing (was 2 updates behind)

- Fans start ramping to max towards end of update

- Computer starts shuddering and crashes within 15 seconds of stuttering starting

- Try turning back on, system shuts off within 2 seconds of pressing power button.

- Wait a few min, try again, POST displays CPU overtemp warning. Shut down and wait 20 min to cool down more.

- Turn on and go into BIOS. CPU temp starts at 70⁰C and steadily climbs to 85⁰C in 2 min. Shut down for the night.

- Next day, same behavior

- Take CPU out, clean off and put distilled water into the IHS hole. Used hair dryer to dry it out.

- Next I put isopropyl alcohol into the hole, and used the hair dryer again.

- Resocketed, repasted and changed back to my GTX 1080.

- Temps in BIOS are now stable at 33-35⁰C, figured the problem was solved at this point because before this it would overheat even in BIOS.

- Boot into windows, CPU hits 90⁰C within 3 minutes, except it doesn't crash. Downclocks to 400MHz and everything is slow as hell, but doesn't crash. I shut down after being on for 10 min.

So this is where I'm stuck. I don't know why it was overheating in OS and BIOS at first, but now after trying to displace any water that may have been in the hole, it only overheats in the OS. I've of course reset the BIOS to defaults as well.

Anyone have any ideas or suggestions? already have another 5820k order from ebay but I'd like to explore what is going on with this one.
Just some rambling thoughts and ideas.

1. Why would you ever intentionally put water into your CPU vent hole? This is more of a curiosity for me and not any help for your situation.

2. Have you tried using an air cooler to verify it's not the AIO. You said there was gunk on it so there's a chance the pump isn't working. There could also be an air bubble creating a blockage.

3. Verify TIM and mounting pressure.

4. I seem to remember an article about lapping Intel as a thing of the past and lapping modern gen CPUs actually increases temps. Don't quote me on this but it had something to do with the convex IHS was designed intentionally to help create mounting pressure. The aluminum IHS actually flexes into proper position once the cooler is mounted. I'll look for that article again.

5. :welcome: to the Forums!
1. I tried blocking the vent hole with TIM during lapping to prevent water from getting in, but I noticed during the lapping that the TIM either got sucked in, out, or just washed off because the vent had some TIM in it but a hole in the center opened up. So my fear (after the first overheating discovery) was that the non-distilled water I was using during lapping got into the vent, so I tried displacing first with distilled, then drying it, then displacing with isopropyl and drying. Which did help with it at least not over heating in BIOS like it was doing right before I did the displacement procedure.

2. Don't have an air cooler but I can verify the pump is working. Outlet hose is hot, inlet is cool. Also had the pump run briefly a few time while topping it off to clear bubbles and gave the radiator plenty of shakes.

3. Everything looks fine there. Nice thin layer when I removed the block and a more even spread than before I lapped.

4. That would be a good article if you can find it. I found references to X99 IHSs being uneven so I figured I'd give it a go since even my idle temps haven't ever been what they should be.

Here's some pictures to of the things I'm talking about:
- - - Auto-Merged Double Post - - -

Oh and thanks for the welcome! 😊
Maybe modern Intel's don't respond as well to lapping, but this isn't a modern Intel. At that time people still lapped.

I'm more concerned with the water in the vent than anything... but IIRC, the 5820K uses the solder paste (?) so it shouldn't matter.
That's the only thing I can think of, that water in the vent has deposited something onto an SMD under the IHS (not the actual CPU die) and it's causing a short. The weird thing is that before I tried flushing out the vent hole, it was rapidly overheating even in BIOS. After the flush-and-dry, it only rapidly overheats in Windows. Thinking that maybe having it de-lidded and cleaned up by a service might fix it, but I just don't know enough about what components are under the IHS to know if that would even help.
Issue solved! Took the AIO all apart again (Lepa Aquachanger 240) and drained it completely except I filtered it through a coffee filter. Next I ran vinegar though the hoses and radiator and let it sit for 5 min. Let the cold plate and pump housing sit with vinegar on them for 10. Flushed with vinegar, then tap water, then did a bunch of flushing with distilled water. Quite a bit of gunk came out. Put the drained and filtered original liquid back in and topped it up with distilled water and reassembled it all. Installed it back in my tower and it's cooling just fine! Even better than pre-lapping, actually, so in spite of the problems I caused myself, I was still successful 😂

I know that putting in fresh coolant would be best, but the point of the project was to spend as little money as possible so I just put the old coolant in. When this thing dies, I'll probably switch to the Arctic Freezer II.

I think what happened is that when I topped it up with distilled water the first time, I did a LOT of shaking to the hoses and radiator and ran the pump for brief 5 second intervals to get any air bubbles out. I think the combination of shaking it a lot, and running the pump multiple times, cause debris to break loose and then pile up at a single choke-point and that was killing the flow-rate. And of course the low flow-rate meant it's cooling capacity went to ****.

Lesson learned!