Extremely Hot PSU

[ricegta]

Hello everyone, I built a new Gaming PC (i7 8700k & 1080ti with 16gb of RAM) and chose an RM750x by corsair for my PSU. The build runs inside the Coolermaster Masterbox Lite 5 RGB which has bad airflow this leading to play without the front pannel (Cooling arround 10°c when I do that). Now the PSU is getting so hot, when I touch the part sticking out from the back mount I can't have my hands on there more than 5/10 seconds. Fans face downward but the PSU compartment is hidden far from all the fresh air coming up front. Is that bad? Im thinking of getting a thermal gun to get the exact temp.Seems to be way too high. Any insight on what it can support? Recommandations etc. Thanks a lot

 

[R0GG]

That's the reason I stay away from the cases with a PSU shroud, under load even a great PSU "deserves" some help staying cool (although built to withstand high temperatures), I have my 5 years old Seasonic X850 Gold with it's fan intake at bottom of case and with it's fan on (not on hybrid mode) with a constant stream of air coming from dual fans placed at both sides of the drive cage (cooling drives and even help cooling graphic card) and all this in open case (no side panels). It runs cool and quiet even while gaming (I ramp up fan speeds through Asus software to 1200 to 1500 RPM).

 

[Karadjgne]

If the fan is underneath the psu, it's drawing fresh air frown under the case, and is not interfered with by inside airflow, shrouds or anything other than if the case is sitting on carpet. There should be no obstructions at the bottom of the case, if there is, that's why the temp is high, the psu is not receiving any air. The case feet are plenty tall enough to clear any airflow restriction on a flat surface.

 

[R0GG]

Absolutely, most modern cases have raised bottom (good height) feet to allow for a comfortable air stream for the PSU, case with bottom fan PSU sitting on a carpet is really a PSU waiting for failure

 

[ricegta]

That's the reason I stay away from the cases with a PSU shroud, at load even a great PSU " deserves" some help staying cool (although built to withstand high temperatures), I have my 5 years old Seasonic X850 Gold with it's fan intake at bottom of case and with it's fan on (not on hybrid mode) with a constant stream of air coming from dual fans placed at both sides of the drive cage (cooling drives and even help cooling graphic card) and all this in open case (no side panels). It runs cool and quiet even while gaming.

Thanks a lot for your feedback. Do you think almost burning my skin is too hot for my PSU? It has 105° capacitors. Might just have to get another case to fix this.

 

[ricegta]

If the fan is underneath the psu, it's drawing fresh air frown under the case, and is not interfered with by inside airflow, shrouds or anything other than if the case is sitting on carpet. There should be no obstructions at the bottom of the case, if there is, that's why the temp is high, the psu is not receiving any air. The case feet are plenty tall enough to clear any airflow restriction on a flat surface.

Here's a representation of my Air Flow :

https://ibb.co/bBdoTy

I believe the Red arrow under the PSU would have needed to be blue since it breath in fresh air right? Not pulling it out?

 

[R0GG]

Yes PSU fan is an intake fan blowing air over it's internals and exhausting it through it's rear plate,
Your GPU fans blow case ambient air (coming from front intake fans) onto GPU components and exhausting it partially through GPU rear PCI bracket shroud and into case counting on it's overall airflow to" dilute it gradually" into case ambient air and exhaust it as it goes through your top and rear exhaust fans.
Your PSU still gets a weak airstream from case front bottom fan which reaches it weakened because of the distance, all you need to do is place another 120 mm fan (with adjustable speed hat you could increase as needed)) at mid-distance between the two to re-enforce bottom front fan airflow, this is relevant even if you have the possibility to remove PSU shroud (which by the way would improve moderately your PSU overall temps with lesser effect when PSU is under load)

 

[Karadjgne]

This is how it should be. The fan pointing down will draw fresh air directly through the psu. There is no feed of air from the inside of the case. Air goes in the psu, air comes out. That's it.

If your fan is exactly opposite, where the fan is pointing up, it draws all its air from the case, none from outside, basically drawing air from a Hotbox with little to no real airflow or intake. This'll create excessive heat.

There is only supposed to be a dust filter in the way of down fan psu intake, if there's a solid surface, the fan will need to face upwards.

 

[ricegta]

Thanks for all these informative answers. This taught me good. From now on what would be my best option? Because let's not forget the rear of my PSU is so hot I can't touch it for long, is this caused by the PSU being bad? My room is arround 26 to 29 while playing. The PSU isnt as hot when im browsing the net or something along this. Should I be worried?

 

[ricegta]

Here's a new drawing showing proper air flow and my PSU location https://ibb.co/cbePLd

 

[R0GG]

Thanks for all these informative answers. This taught me good. From now on what would be my best option? Because let's not forget the rear of my PSU is so hot I can't touch it for long, is this caused by the PSU being bad? My room is arround 26 to 29 while playing. The PSU isnt as hot when im browsing the net or something along this. Should I be worried?

Your PSU has excellent reviews and it's supposed to withstand high temperatures, but if you run long gaming sessions on a regular basis it doesn't hurt to "relieve" it a little bit with some extra cooling, as long as it's fan is facing downwards to the bottom of the case! and case is sitting on hard flat surface with a nice clearance from it, it should be fine.

 

[ricegta]

Thanks a lot! Much appreciated

 

[R0GG]

You're kindly welcome.