Replacing a 240 AIO watercooling setup with air cooling

bazzabear

bazzabear

bazzabear

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This is a bit premature, but I'm hoping I can get some early tips to get me thinking in the right direction as I start to plan.

My (pre-built) PC currently has a Coolermaster Masterliquid Lite 240 AIO cooler in it. It's always been a bit problematic.
If it gets hot enough for the fans to go to high speed, one of the fans catches on the edges of the rad they're attached to and (as you can imagine) makes a racket. I got the fan replaced under warranty but the new one did the same. Eventually I stopped it by adding washers between the rad and fan to give a tiny bit extra space. Or at least I thought I did. Turns out it still happens very, very occasionally. Presumably only when they hit 100% speed and that's very rarely needed.

Anyway, even aside from that problem, they sometimes seem to cause some kind of resonance in the case which buzzes. Not very loud, but the type of buzz that's really quite grating.

I've been lazily putting up with this, because it's sporadic, for 3 years. But I'd quite like to do something about it, and lockdown seems a good opportunity. This is because the PC is usually down low and under a desk and hard to get at to investigate as the sounds happen. With lockdown meaning no visitors, I have wifely permission to have it on a table at the side of my desk instead, which will be messy and in the way - but will give me much easier access to look it over in operation and plan!

Anyway, my initial plan is to just get rid of the AIO set-up and fit a good air cooler and twin 120mm case fans at the top.

Can anyone give me good advice on what case fans and what CPU cooler to go for? And any more general tips, as I'd consider myself a complete beginner despite having tinkered a bit with upgrades and the like over the years.

If it makes any difference, the CPU is an i7-8700k on an Asus Z370-P motherboard.
Case is a cheap thing I've never heard of - a "Game Max Falcon". There's plenty of space for a big cooler (but removing the rad from the case fans will be beneficial as there's not a lot of space in that area of the case next to the DVD drive.)

Depending on what thoughts I get back, I can look closer at how everything currently fits together if it will help. That's my intention for my own planning anyway. I'll pull the PC out and put it on the table this lunch time.

Massive thanks in advance for any advice.
 
OK, now I've got it more accessible, another question occurs to me:

Is there an easier way than using the BIOS, whereby I could test out various fan speeds? This would allow me to try to replicate the resonance issue rather than having to wait for it to get the the temperature that causes the fan speed that causes the issue! :)

I know there's fan controller software out there, but I've no idea what is good or bad, and how it interacts with the rules the BIOS sets.

(Another aside - I know the case has fan controllers, but I don't believe they're in use. Certainly switching the toggles on the case doesn't seem to do anything. I'll try to trace back the wiring from the installed fans to confirm.)
 
Game Max Falcon only has 161mm CPU clearance so that limits cooler height to 161mm. I would use 2x 140mm front intakes with all opening in fan mounting panel to motherboard compartment sealed off so air front intakes push into case has to flow through case and can't leak back in front. Also remove all PCIe back slot covers to increase rear vent area and give better front to back airflow.

Your Asus Z370 P has about 52.8mm center CPU to near side of RAM sockets and 95.2mm to near side of x16 PCIe.

While 161mm CPU clearance does limit what coolers you can choose from there are still many 161mm or less in height. Without knowing RAM height also limits suggestions, but here are a few; Scythe Mugen 5 Rev. B is good, as would be be quiet! Dark Rock 4, Alphenfohn Matterhorn are all about £50. Too bad OcUK is out of Phanteks PH-TC14PE as it is very good and was only £53. Scythe Fuma 2 would be good but out of stock until 30 May 2020. There are some better coolers but they also cost more.

Tell us what RAM you have and I can tell you how tall it is and what coolers will clear it.
 
Just to add to what Doyll has said, dont put a ceiling exhaust fan in front of the CPU cooler, it will exhaust cool air before it hits the cooler

One at the rear directly behind the cooler is enough, another behind the cooler on the ceiling might chop a degree or two off CPU/System temps and isnt really worth it but up to you but definitely dont put a ceiling fan in front of the CPU cooler
 
Cheers guys, that's really helpful, and really interesting too!

I did spot that the current front fans are 120mm only, and thought I might increase to 140.

There's no rear fan fitted currently, just the two top fans drawing air out of the case, through a rad and pushing out the top.

So you're suggesting that I should go with:
Two 140mm at the front intaking air.
One 120mm at the rear pushing air out.
Maybe one 120mm at the rear top, but definitely not a 120mm at the front top.

Do you have any tips for what to use for sealing gaps around the fans as suggested?

Just had a quick look, and the installed ram is:
16GB Corsair VENGEANCE DDR4 2666MHz (2 x 8GB)

Thanks for the tips on CPU coolers too. I'll have a look at them and come back with questions! :D
(I had already wondered about the Dark Rock 4, as I'm sure I saw somewhere that they're well thought of. I'm not averse to paying more for quieter and better performance though.)
 
Get the Asus FanXpert software your motherboard if you are still wanting to manually play with your fan speeds. You could use this to create a fan profile for the fans on your AIO so they don't spin up to the speeds where they cause issues as long as this still keeps your temperatures in check.
 
Another thought, although I don't really see what I can do about this:
It seems rather sub-optimal that the GPU fans push the hot air out of the GPU heatsink towards the bottom of the case - where there is nothing taking it any further.
 
PieEater said:
Get the Asus FanXpert software your motherboard if you are still wanting to manually play with your fan speeds. You could use this to create a fan profile for the fans on your AIO so they don't spin up to the speeds where they cause issues as long as this still keeps your temperatures in check.
Click to expand...

Thanks, I didn't know about that. Definitely like the idea of using software by the motherboard manufacturer, should mean I can trust it!
 
As we've said, you don't need rear exhaust, just lots of rear vent area.

I use tape, it's the easiest way.

Corsiar Vengeance RAM is 52.5mm tall, Vengeance LPX is 33.5mm tall. For comparison standard RAM PCB is 31.4mm tall. I hate how modern RAM has fancy bling marketing Fofo making it much taller but gives little if any cooling but limits what coolers will fit.

Dark Rock 4 is good, but you pay extra for it's better looks.
 
bazzabear said:
Another thought, although I don't really see what I can do about this:
It seems rather sub-optimal that the GPU fans push the hot air out of the GPU heatsink towards the bottom of the case - where there is nothing taking it any further.
Click to expand...
Actually GPU fans push air into GPU. Then GPU's heated air comes out toward motherboard, front of case, side of case and a little toward back of case. This is why good pressure rated front intakes with holes in front half of case blocked off so all air being pushed in has to move back to exhaust out the rear through rear vent and added venting removing PCIe back slot covers create.
 
doyll said:
As we've said, you don't need rear exhaust, just lots of rear vent area.
Click to expand...

Ah! Thanks, I had misread that section of the advice. :)

So basically I'm putting two big fans at the front to suck air in to the case, and then trying to ensure that air has to travel over the components rather than escape anywhere towards the front.
 
bazzabear said:
Ah! Thanks, I had misread that section of the advice. :)

So basically I'm putting two big fans at the front to suck air in to the case, and then trying to ensure that air has to travel over the components rather than escape anywhere towards the front.
Click to expand...
That's the way I do it, and have for years with great results. You will probably find link below is to basic guide to how airflow works and how to optimize case airflow of interest, especially the cheap remote sensor thermometer for monitoring air temp into coolers.
https://forums.overclockers.co.uk/t...-i-put-my-temp-sensor.18564223/#post-26159770
 
Cheers! Very interesting reading, and it all makes sense. You mean tape as in electricians tape or similar?

It makes me wonder whether I should also fit an intake fan at the top front?

The two reasons being:
To avoid that being a big area for inflowing air from the 2 front fans to escape to without passing over components.
Because in it's usual position, my case has something a few inches in front of it for most of it's height - so it would have more direct access to cooler air from just above and in front of it.

Edit to add - I'm doubting whether this is a good idea though based on whether adding an extra fan pointing in a different direction is just going to screw up the airflow.
 
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Electrical, masking, wrapping tape, clear tape, etc.
If using electrical tape be careful to not stretch it as it will sometimes pull back over time.

Potential problem with a top intake as well is it is flowing air down into space front intakes are flowing air back and this can create more turbulence thus lowering overall airflow. Easy to test with and without by monitoring air temp into cooler to see which works best. I prefer using 3x 140mm intake for CPU cooler with 140mm fan/s and 2x/3x 80/90mm GPU cooler fans because 3x flow more air than 2x fans at same speed, and quieter at same airflow becuase they do it at lower speed. All depends on how 1x top and 2x front intakes work vs 2x front.

The simple low cost airflow thermometer are common for terrairums, fridge, etc and can be found on bay or river sites. I like the indoor/outdoor because it shows air temp where it's setting by computer as well as inside. Many have high/low for day references which can be nice to see hottest and coolers airflow was compared to room.
 
I'm not sure if we're trying to help you sort out your airflow with your current AIO setup or with a setup that includes an unknown air cooler. The best advice I can give you is to try to picture your case filled with water with the principle that heat always rises to the top and that you want to direct the coldest water where it matters most, towards the intakes of the fans that direct the cold water to the hot components, your next objective is to get the heated water out of the case.

Keeping the analagy going my own experience is that the fans on the GPU and CPU coolers will suck in a certain amount of cold water from outside the case but there is no real incentive for the heated water in an unventilated case to go anywhere other than up, having as much open space at the rear of the case will help it exit if there is enough force behind it (where intakes come in) but other than that any that doesn't won't be going anywhere but up, so your best first investment is to get the top rear exhaust sorted. Next you want to get cold water directed as far as possible to the intake of the CPU and GPU coolers, so they can make the best use of it, and as Doyll has suggested any additional flow towards the back of the case is usefull if all covers have been taken off so the cold water flowing through can push the warm water out of the back of the case, so your next focus after the top rear exhaust should be front intakes. Baring in mind that we now have a flow of water going from front to back with hopefully some unobstructed flow through to the outside rear of the case and some assisted flow at the top, consider how top / side / bottom fans might impede or assit this, and how your requirements would change if you are trying to direct cold water to an air cooler vs a top mountyed radiator. As per Doyll's reccomendations a cheap internal / external thermometer is really useful if you want to get this right, i.e make sure that the temperature at the apropriate intake is within a degree or two of ambient.
 
Thanks everyone for your help, and your patience with my ignorance!

I strongly suspect that you are right an additional fan up top front would not be beneficial. But definitely something that would be possible to experiment with.

Looking at current connections, I see that the fans on the AIO set-up are plugged into "CPU fan" on the moptherboard with a splitter.

The front fans, which I had assumed were considered chassis fans don't seem to be plugged into the motherboard at all. All other fan sockets are unused. Tracing the wiring for them, it goes back to what I assume must be the cases fan controller. But I can't see where that's drawing power from. Is it possible that it's getting it from the front panel connectors? Because I can't see anything else connected to the motherboard that could be powering them.

In tracing all this, I also see that there's nothing plugged into the USB 3.1 connectors, so my USB3 plugs on the front panel are really only USB2!

When I replace these front fans with 140mm ones, would you ignore the fan controller and plug them directly into the chassis fan connectors on the motherboard?
 
With a bit more tracing stuff back, looks like I was being daft and the fan controller is powered directly from the PSU. Still means that those fans are much less controllable than if they were plugged in to the motherboard, so not sure why it was done that way.
 
bazzabear said:
Cheers! Very interesting reading, and it all makes sense. You mean tape as in electricians tape or similar?

It makes me wonder whether I should also fit an intake fan at the top front?

The two reasons being:
To avoid that being a big area for inflowing air from the 2 front fans to escape to without passing over components.
Because in it's usual position, my case has something a few inches in front of it for most of it's height - so it would have more direct access to cooler air from just above and in front of it.

Edit to add - I'm doubting whether this is a good idea though based on whether adding an extra fan pointing in a different direction is just going to screw up the airflow.
Click to expand...

Front to back air flow where possible. I wouldn bother with an intake in the ceiling, heat rises, it will mess with the airflow and its not likely filtered.

I do use a rear exhaust, I have tested without and found CPU and System temps to be higher but every case is different. I do ensure it runs at lower speeds than the intake fans to ensure positive pressure
 
Not sure I said it so I'll say it now. Make sure you use high pressure rated fans for intake fans. Even fans with high pressure ratings make very little pressure. To give you an idea of how minuscule our fan static pressure is, a fan static pressure rating of 3.727mm H2O is the same as the difference between the air pressure on our body at sea level and 10 feet above sea level. If we measure the air pressure in psi at sea level we get 14.696 psi, if we measure the air pressure at 10' above sea level we get 14.6906 psi. That is only a difference of 0.0054 psi .. the same difference as a 3.727mm H2O static pressure rating is on a fan.
 
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