Bottom mounted fans - worth it?

[Mallers]

Hello, at this risk of sounding like someone who doesn't hoover very often, are bottom mounted fans worth it? Looking at a newer case, and most of the ones i like have space for them, and i wondered if i should get a case fitted for them, and can either install or not. I would have thought they'd just suck up dust collected underneath the case?

 

[mickyflinn]

Most cases have dust filters so that negates dust but blowing air up onto the GPU can only be a good thing.

 

[ttaskmaster]

Experiments by various tech YouTubers of varying reputability suggest that they do suck up dust, and that dust filters either do not stop all the dust and/or restrict the air intake too much.

Personally I find case placement matters more, in that you won't get half as much dust if the case in on a desktop rather than the floor, or close to it.
I prefer to run my intakes open, so I remove most of the mesh/filters and just dust the PC out once a month.

 

[Parsley]

The extra airflow is good for your GPU, as mentioned but if you have your case on the floor consider getting something to lift it up a little so it's not sitting on the floor. (Even something like 5 cm can help). Stops it attracting the dust bunnies at least. Better to have it on your desk if dust is your primary concern though.

 

[cjgardens]

My fans exhaust out the bottom. Intake at teh top. It not only looks better but it also still cools enough not to worry about the direct on the fans. Plus the added bonus of less dust

I have 3 intake at the top, 3 exhaust next to the mobo and 3 exhaust at the bottom.

Because im on water its still very cool

 

[kchakkar]

With the o11 Evo, I have found that using fans under the Gpu, it reduces the temperature by around 3 deg C. I keep my PC on the desk, rather than on the floor.

 

[Gepetto]

I have the O11Air with intake fans on the base. The case sits on the carpet below my desk. I use the dust filters, cleaning them every month although they don't pick up a lot of dust.

As some have said, the dust filters do impact the airflow quite dramatically. Not been an issue for me but I'm running standard clocks on everything.

 

[Drumroll]

Bottom intake will certainly benefit the GPU, but also the NVME next or under the GPU, the chipset and also will help move up and away the hot air coming from the side of the GPUs, as you can easily check how much your NVME, chipset and side panel will warm up if the GPU is under load.
What I noticed is that most fans will sound louder or at least a different “range” than the ones mounted on the top or vertically (front, side and rear). Even The mighty T30 had to be 5-10% lower rpm when installed at the bottom to much noise levels from side mounted fans. Also watch out for clearance e between the mounting area and the fans. Cases like the H9 Flow will make the fan sound much louder than cases like the NV7 or the O11D Evo that uses bottom bracket.
Some fans aren’t affected as much, but for the noisebreaker e loop was the worst scenario I’ve ever had. Fantastic and quiet fans back then, but any mesh or filter too close to the back of the fan and it was loud. Annoyingly loud.

 

[OliverQueen]

TBH I was surprised how little dust bottom mounted fans drag into the system. The Lian Li Lancool II I am currently using has a small mesh fan filter that protects the PSU fan from becoming clogged up & the 2 x 120mm Noctua Redux fans I have placed above the PSU, do a good job of keeping the GPU temps down & when I looked at them the other day during an upgrade, even though the case is on the floor (hard tile so airflow not restricted by carpet pile), they had no dust on them at all after several months of always on usage. The dust filter had a light dusting of dust but that is to be expected regardless & because the lower side panel is metal mesh, I expected some dust to be pulled in through there by the 2 bottom mounted fans.

 

[Troezar]

If your PC is standing on carpet try getting on offcut of wood or similar. I use some wooden worktop and stand the PC on that. Makes quite a difference.

 

[Amidar]

I have the Fractal Torrent and the bottom fans pull in next to no dust I also have it sat on a piece of wood. I clean out the filters every month or so and only the front filter needs much of clean.

 

[beefybarn]

I am using a Thermaltake 500 sat on a piece of 10mm perspex on the floor and it draws in very little dust through the bottom fans, would not worry too much about it.

 

[AMDPower]

in my experience placing it on desk is best solution. The only other thing that worked was hoovering my room everyday and keeping the windows closed, for some reason the windows opened made the pc dusty quick, its kinda counter intuitive. Regardless of where you put it, I would recommend cleaning pc once a month, give it quick clean, if you let it build up its pain to clean.

 

[roachyuk]

I would deffo never have a PC on floor especially carpet as been mentioned in post if need be get a piece of wood or some sort of stand to keep off floor.