Is it ok for a CPU fan to blow into the power supply?

[joeyslaptop]

I'm working on modding a 2001 PowerMac G4 model M5183 to hold the following:

Z490M micro ATX Gaming X motherboard
i5 10500 processor
36 GB DDR4 Ram
500 GB M.2 SSD Hard Drive
700 Watt Power Supply

The case design has the motherboard mounted on the side door, which opens downwards to lay flat on the table. I always thought that this was so cool because you could flip open the door, and laying out in front of you was pretty much everything you needed to get to inside the computer.

The downside is that where the motherboard is mounted, when you close the door, the fan barely fits and blows against the side of the power supply. The case overall appears to have poor circulation. I have been looking at water cooling to get around the issue. Using a water cooler means drilling tons of holes or a few large ones in the bottom of the case to accommodate the airflow from the radiator fans.

However, I'd much rather innovate something that modded the case as little as possible. So far, I've done really well at preserving the case while making minimum mods to it to accommodate the motherboard. One potential work around I've come up with is to flip the power supply so that the power-supply fan is facing the cpu fan. It might seem ridiculous at first, but I have seen super compact systems use a similar technique.

Can I use my power-supply as an exit/vent for the hot air being pushed out of my processor fan? If worse comes to worst, I can reconcile myself to using a water cooler. I just want to avoid it if at all possible.

 

[pastrychef]

I'm working on modding a 2001 PowerMac G4 model M5183 to hold the following:

Z490M micro ATX Gaming X motherboard
i5 10500 processor
36 GB DDR4 Ram
500 GB M.2 SSD Hard Drive
700 Watt Power Supply

The case design has the motherboard mounted on the side door, which opens downwards to lay flat on the table. I always thought that this was so cool because you could flip open the door, and laying out in front of you was pretty much everything you needed to get to inside the computer.

The downside is that where the motherboard is mounted, when you close the door, the fan barely fits and blows against the side of the power supply. The case overall appears to have poor circulation. I have been looking at water cooling to get around the issue. Using a water cooler means drilling tons of holes or a few large ones in the bottom of the case to accommodate the airflow from the radiator fans.

However, I'd much rather innovate something that modded the case as little as possible. So far, I've done really well at preserving the case while making minimum mods to it to accommodate the motherboard. One potential work around I've come up with is to flip the power supply so that the power-supply fan is facing the cpu fan. It might seem ridiculous at first, but I have seen super compact systems use a similar technique.

Can I use my power-supply as an exit/vent for the hot air being pushed out of my processor fan? If worse comes to worst, I can reconcile myself to using a water cooler. I just want to avoid it if at all possible.

I don't see why you can't do it. I use the power supply fan to help exhaust hot air out of the case in one of my builds too.

 

[joeyslaptop]

Is that air coming straight off the processor fan through your case?

 

[pastrychef]

Is that air coming straight off the processor fan through your case?

This is the case that I'm currently using for my Z370 system.

As you can see, the power supply sits on top and the CPU cooler is directly below it. I have my power supply mounted so that the fan faces down and can pull heat from the interior of the case out. As far as I can tell, it's very effective. when I reach to the back and feel the air being exhausted out from the power supply, it's fairly warm.

I did it this way because the little 92mm rear case fan was insufficient at exhausting the heat out of the case.

 

[scottkendall]

Can I use my power-supply as an exit/vent for the hot air being pushed out of my processor fan? If worse comes to worst, I can reconcile myself to using a water cooler. I just want to avoid it if at all possible.

The only issue I can see is that it will force your PSU fan to always be on so you will have the added sounds from the PSU fan. Using a AIO only puts the fans somewhere else the hot air sill needs to be ejected from the case somehow.

 

[jaymonkey]

@joeyslaptop,


In most cases I think it will be fine but it's worth taking the following into consideration.

If your PSU is over specified in terms of its capacity (Watts) then it won't be working as hard as if you have a marginal capacity PSU that does have to work hard to power your system. The harder a PSU has to work the more heat it will generate and dumping the CPU's heat on top of that could result in a shortened life span for your PSU or it may even shut down if it gets too hot and triggers the thermal fuse (if it has one).

Also as @scottkendall mentions above there will most likely be additional internal noise from the PSU's fan to deal with.

Cheers
Jay

 

[joeyslaptop]

So, a 65-watt processor seems pretty safe then. It’s the i5 10500. No over locking or anything, but it probably will be used for processor-intensive tasks.

 

[jaymonkey]

So, a 65-watt processor seems pretty safe then. It’s the i5 10500. No over locking or anything, but it probably will be used for processor-intensive tasks.

@joeyslaptop,

I think you'll be just fine with 65W i5 CPU ...

Cheers
Jay