After installing new thermal paste, your processor is running hotter than usual.
After installing new thermal paste, your processor is running hotter than usual.
Hey! I'm using an older X99 setup—around six years old—with an i7 5820K processor and a Corsair H100i GTX cooler. The CPU has been running hot for some time, usually hitting around 50°C when idle. I thought it was due to neglect, since I haven’t cleaned it in about two years and dust had accumulated a lot. Recently, I cleaned it up and also replaced the thermal paste, which came with the cooler. When I restarted, temperatures spiked significantly, even reaching the mid-60s under light load. In the BIOS, at low demand it hit the high 60s. After switching to Corsair Link, it reached nearly 80°C with only a slight load. I adjusted the waterblock screws multiple times without success. Eventually, I gave up and cleaned the PC more thoroughly, but dust still lingered between the radiator and fans. I tried a deeper clean by removing the radiator fans and scrubbing the gaps. The photos show the fan housing after cleaning—it’s not perfect, but it’s better. There’s one odd spot with stubborn debris between the fins; I used a toothpick to remove it, though it caused some bending. Still, it wasn’t severe enough to cause the overheating. After that, I reapplied thermal paste again. The temperatures stayed high. Just before giving up, I tried another paste change, thinking the original amount might have been too much. This final try was even worse, with temperatures rising faster. Now I’m trying to figure out what’s wrong. Possibilities include low-quality paste, a failing cooler, or damaged heatsink connections. Maybe the thermal interface is broken between the heatsink and CPU. I’m also considering the possibility of a dead processor—though that seems unlikely since I’ve been pushing it hard. Another thought: the cooling system might be compromised, possibly requiring a paste replacement there. That would mean checking the warranty. Testing new paste would cost money, and without another cooler, it’s hard to verify. It could also be that the CPU is no longer functioning properly. Right before posting, I attempted a last-ditch paste change, documenting everything for reference. Photos of prior applications are attached, along with the condition before and after my cleaning efforts. This final attempt was even more problematic. Any advice would be greatly appreciated! If you need more details or images, just let me know.
Possible dead pump. I've worked with a number of early H100i's that died and that corrosion spot on the rad doesn't look good. Evaporation is a thing on an AIO that old as well. I'd be replacing that cooler That thermal paste application looks like far too little. Remember, there is no penalty with too much other than a potentially annoying cleanup. Too little, and that looks like too little, will cause issues like you're experiencing. The conclusion in the article below specifically calls out LGA 2011, I suggest reading it. https://www.pugetsystems.com/labs/articl...iques-170/
The area in picture 3 seems likely a crack or tiny opening in the radiator. With temperatures similar to a car's coolant, if it can't hold pressure, it might struggle to keep the temperature stable. It would probably be better to replace that radiator. As another person mentioned, issues with AIO pumps are common. I also doubted that just a small amount of thermal paste was sufficient; I ended up applying three to four lines across the lid of my 5900X. Usually, if you don’t need to apply small amounts around the edges while tightening, you likely didn’t apply enough. Unless you really need an AIO (which is usually not required), switching to a Mugen 5 or similar would be better for your processor. Two years should be a long time before an AIO works without problems. Edited April 23, 2022 by An0maly_76 Updated with more details
I own an H80i that's only half its age, and air is blocking the pump so no water flows. You could hear air pushing into the radiator after moving it around to clear the blockage. It might help to replace the parts, but you could also try forcing water back in. I had to lay the pump flat and support the radiator before it started working.
You appreciated the assistance greatly! The thermal paste was applied very lightly at first since I assumed the issue might be from using too much. From the responses, it seems I went overboard. I tried another application with a thicker X shape as described in the article, which helped lower temperatures to around 62 degrees idle. It's still a bit high but closer to the original level. I ended up getting a new cooler—this time an air cooler—and it worked well for a long time. Knowing it lasted longer than usual suggests the problem was age-related rather than neglect. I'm confident a new cooler will resolve this.
I think the older model is probably just worn out—this is normal. Let me know if the condition changes after you install a new part.