H100iGTX Noise related to Temp

My H100iGTX started making the most annoying noise last week, kind of like grinding, but if I had to guess I'd say it's air bubbles. I've been closely monitoring the pump and fans RPMs to see if there was a tipping point that sets it off. I also checked for leaks, none. The pump RPM holds steady at 1950, and the fans at 2640 to 2700. The moment the noise starts is when the temp hits 40 degrees celsius. As soon as the temp drops below 40 is quiets and then stops. Then the temp keeps fluctuating up and down every few minutes. How is the temp hitting 40 degrees causing this noise?

I don't know how you can hear anything if the fans are running at 2700 rpm. That is way beyond my tolerance and probably well past the point of meaningful return for that level of noise. Grinding is never good, but if you have the stock fans on still those can do a rather fine impersonation of the love child from a cement mixer and a cheap blender. If the pump is grinding, it should do it all fan speeds and would be most easily detectable at idle.

 

It can also be the pump as well and it seems time for a check up. The normal way to do this is to compare you idle and load coolant temps to the room temperature. Most people have a resting H100i GTX Temp (coolant temp) of +4-7C over their room temp. You would see load temps of +6-8C for pure CPU tasks, like a stress test. You can see more than this in combined loads like gaming, where the GPU and CPU are adding heat to the environment. So, in a 25C room, it is not all that hard to get to 40C, if you are playing hard and have a moderately restrictive case.

 

Can you add some more detail to your specifications? I am assuming the typical 95 TDP CPU, but if you are running a 14 core chip, it rather skews the expectations.

With the fan and pump set to extreme the system idles at 34.1 degrees. It has a i7-3930K CPU at 3.20GHz, 6 cores. Room temp is probably 23 or 24 degrees.

+10C over ambient is a bit high, especially if the fans are maxed out. If I did that, it would be more like +3-4C on a 135W TDP 6 core. How does the 34C compare to other internal case temp measurements, like the motherboard sensor or drive temps?

 

Next time the PC is in a neutral state and cool (like after sleep), run a mild stress test like Intel XTU or AIDA. 10 minutes is plenty. Measure how much the coolant temp goes up.

 

If you take the fans down to a normal desktop level (800-1000 rpm), what happens to the idle coolant temp? The highest pump speed can be noisy on a brand new cooler. Does your basic idle temp go up if you set it to balanced?