Question Few questions I met while overclocking cpu

[kenneth97hk]

Hardware List

CPU : i7-8086k (clock speed 5.2ghz)
GPU : Aorus rtx 3080
Motherboard : Aorus Ultra Gaming z370
RAM : G.skill Trident Z 3600mhz 16GB x4
CPU cooler : Corsair H100i aio
Storage : Samsung evo 970 1TB nvme
Air flow : two nidec gentel typoon 120mm on the 240 radiator in the front panel and 3 nidec gentel typoon 120mm on the top and the back of the case.

While using r20 cinebench to test my system stability, I met few problems.

1. Is it normal the CPU stay at around 90 Degree Celsius in a full load even with a AIO at 5.2ghz clock speed?

2. Normally I'll run R20 for 15times for testing the stability, usually when reaching 5 to 6 times the CPU clock speed will suddenly drop to 800mhz and back to 5200mhz, even though the temperature are not reaching 100 Degree Celsius . This will keep happening unti the test finished.

3. Is it normal the benchmark scores will keep dropping a little bit even with the same clock speed?

 

[CountMike]

Hardware List

CPU : i7-8086k (clock speed 5.2ghz)
GPU : Aorus rtx 3080
Motherboard : Aorus Ultra Gaming z370
RAM : G.skill Trident Z 3600mhz 16GB x4
CPU cooler : Corsair H100i aio
Storage : Samsung evo 970 1TB nvme
Air flow : two nidec gentel typoon 120mm on the 240 radiator in the front panel and 3 nidec gentel typoon 120mm on the top and the back of the case.

While using r20 cinebench to test my system stability, I met few problems.

1. Is it normal the CPU stay at around 90 Degree Celsius in a full load even with a AIO at 5.2ghz clock speed?

2. Normally I'll run R20 for 15times for testing the stability, usually when reaching 5 to 6 times the CPU clock speed will suddenly drop to 800mhz and back to 5200mhz, even though the temperature are not reaching 100 Degree Celsius . This will keep happening unti the test finished.

3. Is it normal the benchmark scores will keep dropping a little bit even with the same clock speed?

1. Depends on cooler's efficiency but voltage also plays big role.
2. Liquid coolers are slow to react on temperature change. first, their mass is large and it may take several rounds of liquid thru system to transfer the heat. It's also possible that you or SW doesn't notice temperature raise of few milliseconds it takes for CPU to lower clocks because of overheat.
3. Yes but that's a multicore CPU so you have to watch each core separately,it's enough for one core to drop seed a bit to lower the score.

 

[sizzling]

A 240mm is fairly average cooling performance, no better than a good (not great) air cooler. I’m not familiar with overclocking a 8086k but seeing high temperatures on a 240mm AIO while overclocking isn’t that surprising.