Exactly what CPUs are you using? Some Intel CPUs use thermal compound and some are soldered.

Are the IHSes of the CPUs flat or are they concave or convex? What about the waterblock?

I had to open up a 939 Opteron because it was overheating due to failed paste between the IHS. I've only seen that once though.

cyclone3d wrote on 2020-07-31, 18:07:

Exactly what CPUs are you using? Some Intel CPUs use thermal compound and some are soldered.

Are the IHSes of the CPUs flat or are they concave or convex? What about the waterblock?

Haswell cpus. I just switched from 4770k to 4790k. I use corsair hydro h105 cooler and I did put grizzly Kryonaut paste between the heatspreader and cooler block. I didn't check about being concave or convex when I installed the cpu. It jumps from 35C to 75C immediately when I start any kind of cpu benchmark and temperature goes gradually up to 80s after that. I just didn't expect that high temperatures with liquid cooling and without overclocking so I wondered if there was something wrong with the 4790k cpu that I just got few days ago cheap.

Edit: Also it does not seem to change temperatures at all no matter if the fans in the cooler are running at 1000 rpm or at max 2600 rpm.

I bet you need to delid and apply some fresh/better thermal compound between the IHS and the die.

Also make sure to clean off the old glue on the IHS and CPU. If it wasn't put on there flat in the first place, the old glue will just hold it cockeyed once it is reinstalled.

Have seen many cpu to heatsink thermal dry up but have never had to del-lid a newer cpu yet as they typically are hermetically sealed and cannot really dry out like a standard cpu + heatsink ..My guess is that your particular CPU (new 4790) may have a seal issue or something else is going on. Did the 4770 have any issues ? Also: where did you get the new 4790 ? If off Ebay you never know what it's story really is. If there is an air pocket between CPU and heatsink it would exhibit same as you describe.

It was used cpu and I got it here locally. The seller didn't know anything about history of the cpu because he buys old computers in bulk and then sells the parts. Only paid 30 euros for it because I thought I could get 10% performance boost compared to 4770k. I don't remember having problems with the 4770k. My motherboard uses speedstep and voltage varies based on the frequency, but I do notice that it makes voltage 1.28V when it boosts to 4.4Ghz and it does boost all cores to 4.4Ghz when using cinebench or prime95 and that is with bios default settings. I couldn't actually find out online what would be the stock voltage for 4790k if they even have one. I was actually considering overclocking the 4790k to get some more performance out of my old computer, but I don't think it can be done when by default the temperature goes above 80C.

I also tried newer version of prime95 with avx and that ended up with 4790k at 100C all cores and thermal throttling to 4.3Ghz
I have never delidded a cpu so I am still thinking if it is worth it to attempt it.

it can dry out.

Curious how old your water cooler is ? I was just reading about someone with similar situation and it was the cooler not the cpu that was the issue. Something about plugged ports inside the cpu block not allowing faster water flow, discovered when they tore it down. Yes could be a dry thermal but you will need good specialized tools to do it and it could damage the cpu if not done proper.

ohh forgot to link it, you might want to read this: https://forums.tomshardware.com/threads/4790k … before.3413994/

Horun wrote on 2020-08-02, 01:05:

Curious how old your water cooler is ? I was just reading about someone with similar situation and it was the cooler not the cpu that was the issue. Something about plugged ports inside the cpu block not allowing faster water flow, discovered when they tore it down. Yes could be a dry thermal but you will need good specialized tools to do it and it could damage the cpu if not done proper.

ohh forgot to link it, you might want to read this: https://forums.tomshardware.com/threads/4790k … before.3413994/

Thanks. I just checked when I bought it. I bought it in 25th of April in 2016. I guess it could be bad but I don't know if the 4770k intel stock cooler that I have would do any better.

I just tested some voltages yesterday. I dropped the voltage to 1.20V in bios and the cpu was still stable and that dropped cpu temperatures to around 70C. Main problem with this is that by manually setting the voltage like this I lost the advantage of adaptive voltage and voltage going down to 0.700V when the speedstep takes cpu frequency down to 800Mhz when idle.