What max coolant temp should I be targeting?


Supreme [H]ardness
Nov 22, 2008
I don't personally like targeting deltas over ambient.

There is an ideal temperature for the conpenents to work at regardless of room temperature, which means if you operate in a warmer environment you need a more serious loop than if you operate in a cooler environment.
That doesn't change anything. If you lived in a sauna you'd OBVIOUSLY have to take that into account.


Limp Gawd
Nov 29, 2011
That is similar to how I have my radiator fan profile setup, but my fans start out at a higher RPM (1300 RPMs) and ramp up from there. For me and my case setup, 1300 RPMs I can barely hear them and these fans top out at 2200 RPMs. At 35C, they start to slowly ramp up to 1500 RPMs. By 40C they are at 1800 RPMs. If it ever gets too hot, they will max out at 2200 RPMs by 45C. Thankfully, in day to day use, it stays below 40C and I only ever see around 40-41C if I am doing an extended CPU burn test. The fans I am using are BeQuiet! SilentWings 3 120mm High Speed PWM fans. Their static pressure rating and noise levels spec'd out pretty well.
Just giving a slight update to my setup.

Yesterday, I decided to move two of my fans over to the top of my 240mm x 54mm radiator, creating a push/pull setup, to see if it made any difference. Idle and low load coolant temps dropped by around 1-2c while maintaining a fan speed of around 1,300 RPMs, sitting between 29-30c (dropping to as low as 28c at night). Running Furmark CPU Burner and Cinebench for extended periods results in coolant temp staying below 33c while fan speeds don't change much, maybe getting to around 1,400 RPMs (I didn't change my fan ramp profile). And while I do have more testing to do to check for consistency, these results are with my ambient room temp being around 4c higher than when I posted my results earlier (winter then vs late spring now). That is certainly lower temps than before all the while the fan speeds stay lower too (which is expected).

Note: my radiator fans are currently not setup to pull cool air from directly outside the case, they are exhausting air out from within the case. But I do have the radiator in its own chamber behind the motherboard, where the power supply resides, and there are 3 intake fans just on that side that feed air into that chamber (2x120mm fans in front and 1x140mm fan in rear all setup as intakes). Aside from the power supply and the D5 pump, there are no other components on that side. As such I expect the ambient temp that the radiator fans are pushing through the radiator are slightly higher than my ambient temp just outside the case. Current ambient temp just outside the case is around 25-26c. Running all my fans at max RPM doesn't help much in being able to getting my idle coolant than the 29-30c it currently sits at when idle. I was able to squeeze out maybe 1c lower at most, so 28-29c might be the floor of ambient temp from within the case. Even my RTX 3090 FE idling is sitting at that same temp. As such, I am probably shouldn't expect to reach any coolant temp lower than that unless I reverse my fan setup and begin pumping room temp air through the radiator first. And if I did that, it might only drop it 2c at most by my guess at the expense of sucking in more dust and hair through the radiator first (which is one of the reasons I have it setup the way I do, to minimize this).