Are those all in one water coolers any good?

[Simon]

i have been considering water cooling my CPU. I expect that any water cooling will be more effective than air. So I started looking at bits and yea it's not cheap. But then I stumbled across these https://www.scan.co.uk/products/corsair-hydro-series-h75-120mm-all-in-one-hydro-cpu-cooler-2x-120mm-sp120-pwm-fans-white-led-pump-in . Well I do wonder if they are any good. I was preparing myself to purchase a dual 140m fan radiator or even 2 of them to make sure I dumped the heat as effortlessly as possible.

Now as it happens I actually work for a radiator manufacturer and potentially could probably drag something out of a scrap bin that does not leak and would not even have to worry about a fan on it. With these radiators costing near what a car one does well... erm...

So my limited knowledge of thermals would tell me that in order for this to outperform my air cooler I need the radiator to have more surface area than the air cooled heat sink. At the end of the day the heat rejection is a function of CPU temperature to ambient difference and the amount of time the system has to blow the ultimate coolant - ambient air - over the radiator to dump as much heat as possible. But do these puny little radiators cut it? Are they no better than air cooled and just a gimmick or a decent entry to water cooling?

[Simon]

Oh well, I just found a 2x140mm one, I've gone with that. It also has a quick coupling in it so that it can be expanded.

[brucehoult]

I have the Corsair Hydro Series H100-110 on my 32 core ThreadRipper 2990wx that uses around 375 W when heavily loaded. This is my first water cooling system ever. I was surprised how little plumbing there is compared to other systems I've seen on youtube. It works fantastic. The machine is extremely quiet even under full load and also stays cool.

[mc172]

I expect that any water cooling will be more effective than air.

You're doomed from the start then. Water cooling is air cooling.

[james_s]

I expect that any water cooling will be more effective than air.

You're doomed from the start then. Water cooling is air cooling.

Don't be pedantic. Water cooling is water to air cooling but that's just semantics, obviously the distinction here is direct air cooling vs water to air cooling. The advantage of water is that it has a tremendous capacity to absorb heat and you can use a pump to rapidly move the water away from the heat source and replace it with new cooler water instead of relying purely on conduction to the heat dissipating fins. Then you can cool the water with a large water to air heat exchanger (radiator) located elsewhere in the case.

The downside is that water likes to leak and having a water cooling loop creates opportunities for a mess.

[brucehoult]

The advantage of water is that it has a tremendous capacity to absorb heat and you can use a pump to rapidly move the water away from the heat source and replace it with new cooler water instead of relying purely on conduction to the heat dissipating fins. Then you can cool the water with a large water to air heat exchanger (radiator) located elsewhere in the case.

Yup, there's a reason why few cars since the VW Beetle have used air cooling.

I can't compare across comparable enough cars but in the early 80s I had a 1980 Honda XR250 motorcycle with an air cooled engine and 1000 mile / 1600 km oil change interval. The XR250 had 24.6 HP while the EPA-satisfying XLS250 had 23.4 HP.

Now I have a 2019 CRF250L. It's essentially the same HP with 24.5 EPA- and EURO4-satisfying ponies (I think around an easy 30 if you uncork the intake and exhaust). But now it is fuel injected, has a cat converter, ABS brakes, and ... is water cooled. And has an 8000 mile oil change interval.

Eight *thousand* miles. Thirteen thousand km. Eight times longer than the 1979-2005 air cooled bikes.

The downside is that water likes to leak and having a water cooling loop creates opportunities for a mess.

I believe the units being discussed come with the water loop already assembled from the factory? I imagine it's pretty reliable.

[when building PCs I specify all the parts myself, but have the store I order them from assemble and test them because they charge SFA for doing so (way way less than my time would be worth) and because they build machines every day while I do it once every few years, so if anything turns up DOA they have other parts to swap in to debug it while I don't]

[olkipukki]

Wow, looks like a water cooling can do a job very well now.

I remember tried it on Xeon without any overlocking way back and one of worst experience - hell noise...

Eventually, I replaced it with beefy Noctua fans and much bigger case where I place EATX+ MB horizontally

[Simon]

I expect that any water cooling will be more effective than air.

You're doomed from the start then. Water cooling is air cooling.

If you read my post I explained that and that the advantage would only be better heat dispersal given more surface area.

[Simon]

I bought this one: https://www.overclockers.co.uk/alphacool-eisbaer-280mm-cpu-aio-water-cooling-unit-black-hs-008-ac.html
It was up against a similar Corsair one that cost less. It does slightly more airflow for slightly less noise. What does annoy me is that none of these products actually come with any specifications. If you ring my employer up and ask for a radiator to be designed they want an awful lot of information more than how big it should be. I picked this one because it can be expanded as a system. I am toying with the idea of dropping the £400 on a Ryzen 9 3900X, it has apart from 12 cores to my R7 2700X's 8, 64MB of cache to my 16MB so much more cache per core and from the little i can tell I need more cache for BOINC/rosetta jobs.

I just tweaked my RAM settings again and dropped tRAS from 31 down to 29 (stock is 42 but this is 3.6GHz @ 3GHz) and now my CPU saturates with 15 work units whereas before it ran 96% so I dropped to 14WU's and now I am back to 96% processor time so looks like I need more data throughput which I will not get anywhere for cheap (one can dream of 4 channel RAM) but I think ultimately that is what the Cache is for to try and make best use of RAM bandwidth and keep as much data local at a time as possible.

However the R9 3900X run's RAM at 3.2GHz, my current board an Aorus X470 ultra gaming say's it only goes to 2933MHz but then if the RAM controller is in the processor what does the motherboard have to do with it other than a PCB layout that can cope.

In the past my R7 2700X has auto overclocked up to 4.1GHz (3.2GHz as bought) as a stock setup if I reduce my core count to 2 cores so I know that it can do the speed but for the temperature.

[SiliconWizard]

I expect that any water cooling will be more effective than air.

You're doomed from the start then. Water cooling is air cooling.

Don't be pedantic. Water cooling is water to air cooling but that's just semantics, obviously the distinction here is direct air cooling vs water to air cooling. The advantage of water is that it has a tremendous capacity to absorb heat and you can use a pump to rapidly move the water away from the heat source and replace it with new cooler water instead of relying purely on conduction to the heat dissipating fins. Then you can cool the water with a large water to air heat exchanger (radiator) located elsewhere in the case.

Yup. Obviously properly done water cooling is more effective than mere air cooling. We've been doing this on car engines for decades. There's no contest.

For CPU cooling, same thing. To get something equivalent with pure air cooled heatsinks, it requires huge and heavy heatsinks, which can be tough to fit on a motherboard/in your case, and can damage the motherboard depending on how it's mounted (some of them are just monsters.)

The downside is that water likes to leak and having a water cooling loop creates opportunities for a mess.

Yup. Had a Corsair H100i (first version I think) and it leaked after a few years of operation. I should have been more cautious; a couple months before the leak happened, I had done some maintenance on this computer and noticed very light cracking on the tubing. I didn't think much of it at the time, bad idea. Anyway, it leaked right over the graphics card as is usual, and it killed it. Fortunately nothing else was damaged.

These days I would recommend Alphacool (which I now have) or Be Quiet solutions instead of Corsair.

[wraper]

AIO water coolers do not provide better cooling than good air cooler, some are even significantly worse. They are not more silent as well. Also you should expect that it likely won't live more than 4-5 years. Not to say there is quite high to ignore possibility it will leak and destroy your computer. IMHO the only reason to use one might be for transportation. As heavy heatsink mounted on MB is not good for transporting without additional support.

[Simon]

The problem with air cooling is that heat does not actually move in solid metal that fast. I did an experiment with a heat sink and a power resistor and looked at the heating of the heat sink on my thermal camera. The heat really does not creep up the metal that much. The local fins dump most of it and then there is not enough temperature differential to push it further up the heatsink. The answer is to collect the heat, take it away and then dump it.

Radiator fins are designed to turbolate air and get heat out in a way that extruded heat sinks cannot. They have far more surface area.

[Simon]

AIO water coolers do not provide better cooling than good air cooler, some are even significantly worse.

is that compared to a put it together yourself system? At the end of the day i cannot buy the component parts for what this costs, it's 2x 140mm fans which is far more air volume than the 80mm fan on my stock heat sink.

[wraper]

For CPU cooling, same thing. To get something equivalent with pure air cooled heatsinks, it requires huge and heavy heatsinks, which can be tough to fit on a motherboard/in your case, and can damage the motherboard depending on how it's mounted (some of them are just monsters.)

Nope it's not. Air coolers have heat pipes which work like water transferring heat to large radiator.

[Simon]

Not the stock ones.

[wraper]

is that compared to a put it together yourself system? At the end of the day i cannot buy the component parts for what this costs, it's 2x 140mm fans which is far more air volume than the 80mm fan on my stock heat sink.

You can buy air cooler with two 140 mm fans if you want. Quite ridiculous comparison with stock cooler. But generally there is no big reason to go above 120mm fan unless you do extreme overclocking. Water cooling might have some advantage only if you build custom loop for cooling GPU as well.
Test results starting from 3:50

[wraper]

Not the stock ones.

Buy higher end AMD and you will get stock cooler with heat pipes. Again comparing measly stock cooler and AIO is ridiculous.

[wraper]

The problem with air cooling is that heat does not actually move in solid metal that fast.

LOL what? What solid metal? There is fluid inside them. And they transfer heat very fast.

[Simon]

Not the stock ones.

Buy higher end AMD and you will get stock cooler with heat pipes. Again comparing measly stock cooler and AIO is ridiculous.

As I said above I can get my CPU to 4.1GHz by just turning so many cores off that the 2 remaining cores have so much cooling that they overclock by themselves without me having to do anything.

[Simon]

The problem with air cooling is that heat does not actually move in solid metal that fast.

LOL what? What solid metal? There is fluid inside them. And they transfer heat very fast.

Not all, a lot of the stock coolers usually for sub 85W CPU's are a copper core heat shrunk into an aluminium tube with fins coming off it.

[wraper]

I did an experiment with a heat sink and a power resistor and looked at the heating of the heat sink on my thermal camera.

Did you mind painting heatsink surface or at least attaching a piece of adhesive tape on it's surface? By default it works like mirror for IR, so you won't see actual heatsink temperature by IR camera. You may look at piece of metal heated to 100^oC and see 40^oC reflected from something else. I suspect you don't know how to use IR camera properly.

[wraper]

The problem with air cooling is that heat does not actually move in solid metal that fast.

LOL what? What solid metal? There is fluid inside them. And they transfer heat very fast.

Not all, a lot of the stock coolers usually for sub 85W CPU's are a copper core heat shrunk into an aluminium tube with fins coming off it.

I thought you were talking about solid metal heat pipes. Yet again, even mentioning cheap stock coolers in AIR vs AIO comparison is ridiculous.

[Simon]

i don't think i will be able to fit a huge air coolor. At the moment I have a ton of fans anyway. For all the hype the manufacturers make about their fans they never give performance and with good reason, they are all shit! If I get the radiator outside of the case i can easily make an adapter for ebmpapst 4114 series fans, those kick ass and on their minimum speed will outperform any over-hyped junk that all PC accessory makers sell.

[wraper]

i don't think i will be able to fit a huge air coolor. At the moment I have a ton of fans anyway. For all the hype the manufacturers make about their fans they never give performance and with good reason, they are all shit! If I get the radiator outside of the case i can easily make an adapter for ebmpapst 4114 series fans, those kick ass and on their minimum speed will outperform any over-hyped junk that all PC accessory makers sell.

What is your CPU? As your stock cooler does not even have heat pipes, I guess $40 mid size air cooler should be more than enough. If you watched that youtube video, small air cooler beats small AIO.

For all the hype the manufacturers make about their fans they never give performance and with good reason

There are tons of cooler reviews with performance comparison charts.

[Simon]

In fact I can tell you why water versus air is the same. The fans are so awful that they push less air through a radiator than the straight fins of the air cooler, Radiators present a not insignificant pressure drop because the air is made to go the hard way. Even on vehicle radiators the fans have to be carefully chosen because air flow is not everything, if the fan does not have the pressure to get air through the radiator - game over.