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Area51 R4 thermal control causing audio distortion

BeemerBiker

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Joined
Feb 14, 2018
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I am getting really bad distortion across all sound systems: Video -> HDMI -> cheap monitor speakers or Realtek -> green jack (front or back) -> Bose headphones.
I posted at dell community but had to edit my post as they didn't like the word NVidia. I edited it to n.vidia and the post was accepted but never showed up.

The problem is distortion while playing music when choosing the manual "curve" control. I would think this is a software problem since the other forms of temperature control do not cause any distortion whatsoever. Can someone here verify this for me? It can be done by playing any quality mp4 and bringing up the Alien Thermal control and doing the following:

1. Select "Auto" and click on APPLY: There should be no distortion on headphones or from video board HDMI to monitor speakers.
2. Select "Manual" and "fixed" set RPM to 0 for all 3 sensors, click APPLY and observe no distortion
3. Repeat 2 but select 100% RPM and observe lots of fan noise but no distortion after clicking on APPLY
4. Select "Manual" and "curve" for all 3 sensors and click on APPLY: really bad distortion regardless of any fan speed.

My CPU, 7900x, runs too hot and I disabled hyperthreading in addition to setting the manual control up to %70 on the CPU fan. However, the so-called "CPU fan" is really the front fan and not the fan that expels air thru the water cooling CPU radiator. I am tempted to swap those fan controls or add a 2nd fan in push-pull on the radiator. there is also an unused space for an additional fan in the front that could be used but I suspect the radiator cooling is the key.

This system runs BOINC while idle and that causes the CPU temps to rise. That "auto" fan control works fine when system is normal, but when BOINC kicks in the preprogrammed temp control is insufficient. Whether under any load or totally idle, the audio distortion is highly noticeable when "curve" is enabled.

[EDIT] The CPU fan is the correct fan but the one at top front makes more noise which misled me. I think the heating problem can be solved with a thicker radiator. Since the fan is just a 120mm they should have used a thicker radiator such as the Hydro H80i. This system should have been designed around 140mm fans as they are potentially more efficient and can run at lower RPM with less noise. I can feel the heat rising from the surface of the radiator. That should not happen as the air flow should pull the heat outward. However, that possibly could be on account of having the side case off which causes a loss of pressure but it does suggest an insufficient air flow.

I added a 4pin fan on the unused AUX connector for push-pull mode on the CPU. So far works OK but probably needs to be synced to the other radiator fan. Speedfan shows it at 810 rpm with 2020 rpm for the main fan. Since the radiator is the bottleneck the RPM imbalance has little effect. There is noticeably more air coming out the exhaust. However, when I select "manual" and triple the speed of the CPU, PCI and TOP fans, the new fan I added drops from 820 down to 680-700 rpm. Not what I expected at all.

[EDIT-2] I connected that AUX fan to 12v directly but left the tachometer wire in place. RPM was virtually constant 1600 no matter what setting the other fans were. This suggests the MB caused the RPM drop.
 

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