Gigabyte G-Power 2 Pro CPU cooler

Cooling
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TIME TO STRIP... THE FAN & SHROUD

It seemed the only thing to do. There wasn't much more to be done in the way of testing, and we'd at least learn more about the shroud and the fan.


We began by unscrewing the fan. It's attached to the shroud with three screws that are just accessible between the fan blades. This did not release the fan because its power lead was attached to some other part.

Then came two screws at the bottom.

It was difficult to find the top screws for the shroud/frame, but they were found in the end, hidden under the logo tag glued over them at the top.

We discovered that the fan is an Everflow T121225SM, rated for 0.25A at 12V. The frame, as suspected, is made of a brittle-hard plastic, and the struts to which the fan was attached are quite easy to flex.

Here, finally, is the bare heatsink.

The first thing to do was check the specifications of the Everflow T121225SM fan. The closest match in the Everflow on-line catalog was the R121225_M. The M stands for medium speed, which they specify as 1800 RPM. We measured higher (2200 RPM) but this could well be within product variance. The S before the M stands for sleeve bearing — we were wrong when we wrote that it sounded like a typical ball bearing fan; that could have been an effect of the plastic vibration noise. Finally, the SPL is given as 34 dBA. The only other Medium speed (1800 RPM) 9-blade 120x25mm fan in Everflow's catalog was the LED version of the same fan, with an SPL rating of 34.7 dBA. Note that the maximum noise in Gigabyte's specs is given as 23 dBA.

The fan was re-attached to the frame, then listened to on its own without any impedance nearby. It was also measured again.

Everflow T121225SM fan
from Gigabyte G-Power 2 Pro
Fan Voltage / RPM
SPL by itself
(dBA@1m)
SPL on heatsink
(dBA@1m)
12V / 2250
33
37
9V / 1280
26
29
7V / 100
22
25
5V / 700
18
20
4V / 530
<18
<18

The numbers are plain enough: On its own without impedance, the fan is much quieter. What the numbers don't tell is how much smoother it sounds. Much of the harsh, unpleasant, tonal qualities heard originally (with the fan mounted in the shroud on the heatsink) were just gone. Listened at very close distance, the fan still had some of the buzzy quality that's so prominent in the G-Power 2 Pro, but it was low enough in level as to be inaudible from a meter away. Interestingly, all this was still with the fan attached to the shroud.

Our hypothesis, then, is that it's not just the shroud vibrating in the G-Power 2 Pro, it's the shroud and the metal structure of the heatsink itself. Dozens of thin aluminum fins, attached to the plastic shroud which easily passes on the vibration of the fan, all vibrating together — that is what's responsible for the sound we hear in the G-Power 2 Pro.



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