CPU running hot on water
CPU running hot on water
I have an i7 8700k overclocked to 5ghz on 1.304V, with a Corsair H100i v2 cooling it. While playing games it usually stays between 50-60°C, occasionally reaching up to 70°C which was acceptable. Recently I started video editing and noticed temperatures rising into the 90s. I ran Prime95 and it crashed during stress tests, freezing for 10 to 60 seconds in Blender when temps hit 90°C. It seems my system shuts down once it reaches around 95°C. I’m unsure if the issue is with the cooler placement or insufficient thermal paste. This was my first experience with watercooling and overclocking, so I’m not sure if I made a mistake. Any advice would be greatly appreciated.
I chose to open it up, and there it was—the issue. I’m not sure how, since during installation I double-checked everything and tightened everything properly, but the thumbscrews on the cooler had become extremely loose. I managed to move around the cooler a lot, and I think the temperature drop was due to bad contact between the CPU and the cooler. It’s possible the vibrations in my room (being right above my washer and dryer) might have loosened them, but I did retighten them and now everything works fine. Still planning to lower my overclock to 4.9 ghz for safety and stability.
I believe you're taking it a bit too far. Both video compression and prime95 rely on AVX, which significantly raises the temperature. It seems your system clearly can't cope with that under the current voltage, and the H100i, while decent, isn't a fully reliable professional solution.
I have an i7 8700k overclocked to 5ghz on 1.304V with a Corsair H100i v2 cooling solution. During gaming it usually stays between 50-60°C, occasionally reaching up to 70°C which was acceptable. Recently I began video editing and observed temperatures rising sharply into the 90s. I started using Prime95, which caused immediate crashes during stress tests. The system would freeze for 10 to 60 seconds in Blender when temperatures climbed past 90°C. It appears my computer shuts down once it hits around 95°C. I’m unsure if the issue lies with the cooler placement or insufficient thermal paste. This was my first experience with both watercooling and overclocking, so I’m not sure if I made a mistake. Any advice would be greatly appreciated.
It's approximately eight months since the H100i V2 was released.
If prime95 crashes right away, your overclock won’t work well. I’d run prime95 at 26.6 with that CPU—it lacks AVX instructions, unlike the newer version, which is better for gaming PCs. It idles between 50-60°C, which is too high. Your cooler might not be installed correctly, the pump could be faulty, or your BIOS settings are wrong. A 1.3v Vcore wouldn’t explain such temperatures, have you adjusted any other voltages?
A 8700 on a H100 running at 50C is already a concern worth mentioning. With the temperature rising, I’d be keen to confirm whether your Water Pump header on the cooler is fully locked in BIOS and via the Corsair app. I’m fairly certain it’s set that way, since it shouldn’t be possible for the CPU to hit 95C during a H100 run. If not, consider lowering the AVX multiplier in your BIOS by four clock cycles below the CPU base frequency. Remember, AVX isn’t meant to operate at the stock speed—Intel specifies otherwise. It’s not just 64-bit; it’s a 512-bit VLIW architecture that produces significant heat when handling multiple register banks or processing many numbers per cycle. This can push power consumption up to eight times higher per core, making it very hot. After adjusting AVX throttling to about 400mhz below the stock speed, test performance with applications like Blender or Adobe Renders under these conditions. It would be reasonable to say someone evaluated the modern core and realized the need for AVX to handle multiple operations simultaneously.
I chose to open it up, and there it was—the issue. I’m not sure how, since during installation everything looked fine and I tightened it just right, but the thumbscrews on the cooler had become extremely loose. I managed to move around the cooler a lot, and I think the temperature drop was due to bad contact between the CPU and the cooler. It’s possible the vibrations in my room (being near the washer and dryer) might have loosened them, but I did retighten and now everything works normally. Still planning to lower my overclock to 4.9 ghz for safety and stability.