I plan on building a high end gaming PC this summer with these specs:

CPU: Intel Core i9-9900KF GPU: Nvidia RTX 2070 Super RAM: Corsair DDR4 64GB (4x16 GB) at 3000mhz Motherboard: Gigabyte Z390 LGA1151 SSD: Samsung 860 EVO 1TB M.2 HDD: WD Black 6TB 7200rpm 3.5” PSU: Corsair RMx 850W 80+ Gold Case: Thermaltake V100

I have a ‘Be Quiet Dark Rock Slim’ CPU Cooler, but I want to put an AIO Cooler in the build. I am worried that my i9-9900kf will run too hot, and won’t allow proper cooling if I want to overclock the CPU. I have space in my desktop case for a 3 Fan or a 2 Fan AIO Cooler. I want to know if I would see any temperature difference in the two fan AIO cooler vs a three fan AIO cooler at base and turbo clock speeds. I am still indecisive on what AIO cooler I want since I haven’t done good research in the AIO cooler market.

1 Answer 1


It is not the heat flow (aka Watt) that makes CPUs like the I7-9900K(F) run rather hot, but the high heat flow density (Watt/m²). These chips are pretty small. Hence the limiting factor is heat transfer from the CPU die towards the coldplate and into the water, not heat dissipation of the radiator.
A 240mm radiator is more than capable of dissipating the heat flow from these CPUs, there will be little to no difference compared to a 360mm radiator, provided CPU block and water pump are the same. If 2-3 degrees are worth the investment to you, then go for a 360mm radiator. Otherwise, 240mm is enough.

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    Not really. Realistically, you won't get much more than 200W of sustained power consumption for daily use. This is still not enough to overwhelm a 240mm radiator. Generally speaking, CPU power consumption is rather low during gaming sessions. In a GPU-limited scenario, the CPU is not fully utilized. And most CPU-heavy titles still don't make use of this many threads, leading to lower CPU power consumption.
    – user13807
    Commented Feb 11, 2020 at 17:05
  • Would there be a noticeable difference if I overclock my CPU? i'm coming from using a gaming laptop that would run 70c on CPU at 95% utilization and 65c on GPU at 90% utilization (i5-730HQ and GTX 1050) so I'd like to get those numbers as low as possible. I'm not super worried about price as it is a high end PC. Commented Feb 11, 2020 at 17:06

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