Fan upgrade advice

[ninjag]

I was going to pull my four 120mm Noctua fans from the old build into my new one and so far I've moved two as I'm still running my old rig, but as I'm now in a large case which can take 140mm fans I think I'm going to move the 120mm oones back (and ultimately use them all in my son's new build).

So, I'm looking to get three PWM 140mm fans for the ASUS TUF Gaming GT501VC case in the following setup:

Front: x1 intake (fine metal mesh filter)
Top: x1 exhaust (fine metal mesh filter)
Rear: x1 exhaust (no filter)

I'm not sure if the mesh filters are fine enough to warrant static pressure fans or should I just stick with high airflow ones? I'm not bothered about RGB.

The Noctua NF-A15 caught my eye but I would love some other suggestions and manufacturers if anyone would be so kind?


Thanks

 

[ninjag]

Thanks, a few too many caused an impulse purchase of five Corsair ML140 lol

I don't mind negative pressure, I prefer to pull hot air out rather than try and push cold air in and the computer is raised up a little in a fairly clean environment. It's how I ran my previous built and it stay pretty clean so I'm hoping for the same.

The setup I have planned is:

x2 intake fans at the front primarily to create airflow and push towards the exhaust
x2 top exhaust fans to help pull out the heat being pushed and pulled through the CPU cooler's two fans which flow upwards to the roof)
x1 rear exhaust fan to assist with pulling out heat in the case

I thinking was that by having more fans I can run them at lower rpms so quieter and it will give me options to play about. Whilst the air in the room won't be cool, if the case is full of holes I can experiment with positive pressure and pushing the hot air out (rather than push cold air in if you know what I mean) by increasing the rpm on the intakes and have the exhaust fans just ticking over.

The fun begins! lol

 

[ninjag]

That setup would create "negative pressure" meaning air getting sucked in from every gap and hole, because of more exhaust than intake.
Would be better to have two fans as intake especially if you're going to keep case on floor and aren't big on cleaning your room.

Also unless fans are powerless they simply push out excess air not removed by exhaust fan out from case.
Nature just doesn't allow pressure excess if there's any way for air to move.
And that case has plenty of holes.

Arctic P14 would be superb for the wallet friendly price.
https://www.overclockers.co.uk/search?sSearch=arctic+p14
Best to take PWM versions for good speed adjustability.
PST model comes with splitter built into cable to allow chaining another fan into same motherboard header.
Which comes handy for multiple intake fans.

Aye, you are right about that! After having a good look and playing around with various combinations (including having the CPU heatsink blowing up to the top case fans) I don't think this case is very good for a negative pressure setup. So, I've now got positive pressure (hopefully) and I've tried to have a good think about airflow.

Here's what I think is happening in the case with the 140mm fans (top and front are magnetic metal mesh filtered), I'm hoping I've got good airflow blowing over both the RAM and the M.2 SSD whilst also getting the GPU heat away out the back. I ran a simple stress test for a while and the temps seem ok with the fans remaining quiet (I've got custom profiles setup).

Any thoughts or advice would be most welcome!

 

[ninjag]

Are those fans on the GPU really pulling hot air from the GPU itself and not blowing cooler air onto them?

There's some slight concern about the top fans, with one intake and one as exhaust so close to each other. As that can recycle some of the hot air back into the case, not a lot, but some. Turbulence and disrupted airflow are normally the main concerns about that if I'm not mistaken. Although in some scnearios, it's actually not that bad a deal, so it depends. I personally have done the same and partitioned them off from another at the top of the case I'm using, so the airflow gets diverted away from each other. Also helps a bit with sound reduction (not a lot), but better than none.

If any of your devices have zero fan RPM modes (like the GPU), be aware that when they turn on, it'll momentarily disrupt the airflow in the case, and also cause an increase in temperature throughout the case, even near the Intakes at the front of your case. This will cause a small temperature spike every time until it (usually very quickly) settles back down. So something you might need to keep an eye on for any fan curves that they take this into account. Too long curves may not cover the increase, and too aggresive and it may start sounding bad.

Thanks for the detailed reply.

Top fans: I was worried about these and I'm hoping the CPU heatsink acts as a form of barrier to prevent turbulence as it's a little closer than my diagram portrays. I was also a little worried about the metal mesh filter acting as a kind of heatsink and spreading heat over to the intake fan, but when I feel the filter it's nice and cool over the intake and warm over the exhaust fan with clear separation in temperature. I am a little concerned about the mesh filter inhibiting airflow from the exhaust fan though, maybe I would be better having both as intake and going super positive pressure? I could keep the intake rpm's low and increase the rear exhaust rpm to compensate.

GPU: Sorry the diagram probably doesn't show it very well but the fans on the GPU are blowing inwards and into the GPU heatsink and then I'm showing the heat being pushed out from the top and bottom of the card where the exposed heatsink is and then circulating into the case where I'm hoping my intake fans will help carry this hot air out towards the rear of the case.

Zero Fan RPM: The only fan which has a 0rpm is the tiny chipset one. It won't kick in until something like 65°C I think? It's the built in silent profile.

I've configured my fan profiles so that the CPU and the case fans are set to react to the temperature of the CPU. I did this because the case never seems to get above 40°C and it's only the CPU which gets a lot hotter. But, I've also noticed that the temperature of this processor can sometimes randomly move from about 35°C to about 52°C during normal operation (i.e. non-gaming) such as when I open Photoshop. It will then quickly drop back to the 30's. I think I read somewhere recently that this is common, so I've designed the fan profiles to take this into account so that my fans don't keep engaging and the system stays nice and quiet but when the temp starts to properly rise when gaming then things get more aggressive with the fans. I don't mind as I've got headphones on. I'll take a picture of my profiles from BIOS next time I restart.

Is there a thread anywhere on here where others have posted diagrams of their fan setups? I find it quite fascinating the whole science behind it.


EDIT: I forgot to say that I did initially have two CPU fans but that only worked when the flow was going upwards. Now that I've changed the orientation of the heatsink, if I put a second fan on to pull heat out of the heatsink it will be about 1cm away from the case exhaust fan. I decided that this was too close, plus it closed up all the air space around the case exhaust fan.

 

[ninjag]

This is where I've ended up at and hopefully airflow is good?

Rear exhaust at a slightly higher rpm but all pretty much silent unless gaming. Only the annoying GPU fan is audible as it won't allow me to set it below 42%.

CPU temp doesn't seem to breach 65°C when playing ARMA 3 which I'm happy with.

 

[ninjag]

Thanks for the detailed reply and setup. Aye as you say it's similar to my previous setup but I think my metal mesh filters were not allowing the top exhaust fan to exhaust probably without ramping up the rpm and subsequently creating too much noise.

Is that a fan you've got installed between point 3 and G? It's an area of concern that I noticed in my setup as I don't think I can get a fan in there but it's an open mesh, so I decided to change my setup to positive pressure and therefore making this point a passive exhaust area.

My only source of noticeable noise now whilst under regular use is that 1660 Super because I can't set the fan below 41%. Once graphics cards are back in regular stock I think I'll upgrade and pass this one onto my son.

 

[ninjag]

Ah. That's unfortunate. The top of my case is just hole punched rounded hexagonal holes and not a mesh, otherwise I may have ran into the same issue you did.



It is yes. I found that when the GPU fans go from zero RPM mode to active (40% fan speed, swapped the original fans with two Noctua A12x25s) and when that happens, that forces warm air all around the case and sort of "pushes back" against the incoming cool air from the front of the case. To help circumvent this, I placed a Noctua A14 (spare) at that location so when the GPU fans do kick in, more of the air is being directed towards the rear and top of the case, where there are fans helping to exhaust them out.



Yeah, my GPU can't be set below 40% too. The original fans on the RX580 GPU, were "bad" (noise wise for the performance, performance was good, but noise level wasn't as desirable as I wanted). So I found out from a dismantling video that it's possible for the GPU I had to mount fans on myself because there was no raised points that would interfere with any fan blades. So that's when I grabbed the Noctuas and slapped them on using some zip ties to have the performance of the fans at the noise level I wanted.

Being able to game in the middle of the night and wondering if your PC is even on (from lack of noise unless you put your head down to the case) is excellent. It's reached the point where during the day I've failed to boot up the PC on many occasions, because I didn't hit the power button properly and didn't realise it because I can't hear the fans or see the power LED on the case.

If you ever consider to slap some alternative fans onto your GPU to reduce the sound output from it, make sure you check for any raised points that might interfere with the fans you attach. And to grab those mini-PWM header to normal PWM fan cabless to allow normal fans to be controlled by the GPU.

The mesh filter at the top of my case is that magnetic removable kind, but it's the whole length covering both fans so not ideal. Thanks for the other info, food for thought.

 

[ninjag]

Because of the length of my case I am a little worried that my front fans aren't pushing enough air to the rear of the case where the graphics card is, unless I up the rpm and make it noisy. So I used my spare 140mm Alpenfohn Brocken 3 fan and installed it (via magnets to the rear metal of the case) perpendicular to the graphics card (well, there's a very slight angle towards the rear passive exhaust) so that it blows into the area in front of the graphics card fans to be sucked in.

I'm not sure if this will mess up airflow and I've not tested it properly but I've felt that this area between the graphics card and my Sound Blaster Z has been a bit of a hot spot.

 

[ninjag]

Like this, although my scales are a little out

 

[ninjag]

I suppose the question here is, are there vents behind that new fan addition on the side of your case so it's bringing in cool air from outside the case? If not, you might be breaking the airflow and not really making things any better, because you're trying to take a straight flow of air and bending it 90 degrees. Someone more knowledgeable will be able to fill you in on the details on that, but I remember it's considered a no-no.

But if you've noticed a bit of a hotspot there and it is helping, I'd leave it be. Although I'd be tempted to see, if physically possible, to place it between the front fans and the GPU aimed towards the rear of the case to test if viable too. In theory, the fan won't need to work as hard because its getting air from the front fan, so all it needs to do is keep pushing it to the left/rear of the case. Any cards there, assuming the rear PCI plates are off, should attempt to exit that way more easily, whilst carrying heat away from the PCI area and bringing in more cool air from the front.

Yep, this was exactly my first concern. My old case had vents in the side panel and a fan mount, but this one doesn't and as you say there is air flow to consider. It is slightly pointing towards the rear but not enough to act as a push through I reckon.

My initial plan was to actually mount it in front of the graphics card just as you say to help push the air on, but I thought my PSU shroud was metal and turns out it isn't, so the magnets don't work. I'll look at using some double sided tape and stick a small piece of metal on it as I think it would be a far better solution.

I'm also wondering if there's heat soak transferring from the CPU heatsink. I've got a spare PCI plate above the GPU, I wonder if you can buy some sort of bulkhead/heatshield which can screw into that PCI plate in the rear of the case?


EDIT: Was also thinking about a PCI slot fan array but to go above the GPU and blow against the CPU heatsink therefore away from the GPU? My CPU and other temps are all good, it's just the GPU which is getting a little toastie when mildly overclocked.

 

[ninjag]

I've relocated the fan so that it is in front of the GPU and being assisted by the front case fans, but I'm getting a strange resonance now which I'll need to deal with. It disappears when I remove the side glass panel, so I'll maybe open up the rear PCI slats again and see if that helps.

One thing I've noticed with these Corsair ML140 fans is that there's no direct airflow from the centre of the fans and it all seems to come from the edges and goes out at a bit of an angle. Airflow doesn't feel great when running at low rpms. When cranked up to 100% they are awesome, but also very loud.

The spare 140mm Alpenföhn fan from my CPU cooler seems to be much better at having direct airflow straight from the fan (could be the fin design?) and definitely pushes out more airflow at lower rpms and therefore much quieter. I'm tempted to replace my Corsairs with a few of these: link

I'm also thinking I might be becoming a little obsessed with airflow lol

 

[ninjag]

Cheers, I removed the rear plates and it improved things and also dropping the rpm by a hundred has pretty much made it disappear. My GPU temps have come down a little, so I'm pretty happy now. I was thinking about some ducting from the front lower fan straight to that area below the GPU, but now I have the fan it's not necessary.

 

[ninjag]

Spent yesterday and a little today clearing out the eaves storage and came across my big box of old computer stuff, including an old and very heavy metal case Dell XPS computer (which had an old school Sound Blaster X-Fi card in it! From the boxes and the XPS I've also found two old graphics cards - not sure of the models, I think one is an 8800 GTX.

Anyway, this has now presented me with a possible small project as I was looking for some sort of bulkhead to go between the graphics card and the CPU heatsink to prevent heat soak. I can't bring myself to use the X-Fi card, but I could strip the 8800 back to the board, modify it into a single slat (as that's all I have above the 1660 Super) and then it's a case of what material to attach to the board to either reflect heat away from the graphics card, although this could result in it soaking back into the CPU heatsink, or some sort of material to soak up the heat from the CPU heatsink and disperse. I could even use the 8800 heatsink?

Any thoughts on this and is it even worth trying? My GPU temps are fine so long as it's not overclocked, but that's not much fun.