Why you shouldn't water cool your PC
Linus Tech Tips
·Linus Tech Tips
·2019-05-06
·
2,415 words · ~12 min read
0:00
So you're building a brand new PC
0:01
and it's time to choose a cooler for your CPU.
0:05
There are so many options out there,
0:07
but before you even really get into the weeds,
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you've gotta make one choice.
0:11
Do you cool your PC with a large air cooler
0:15
or with an all-in-one liquid cooler?
0:18
Now, if we can trust the marketing,
0:20
AIOs are the clear choice.
0:22
Water transfers heat so much better than air, right?
0:25
But is that the entire story?
0:27
Maybe, actually.
0:29
I don't know.
0:29
Alex has been working on this in isolation
0:31
and I don't know the test results.
0:34
So I'm just as eager to find out as you guys are.
0:47
Now, before you run out and buy a new CPU cooler,
0:49
you need to first figure out if your CPU
0:51
is gonna get any benefit from additional cooling.
0:54
Now, in the old days,
0:55
inadequate cooling was a recipe
0:57
for instant catastrophic failure
0:59
because the modern protection or throttling mechanisms
1:03
that prevent them from exceeding
1:04
the generally accepted maximum,
1:07
of a hundred degrees Celsius,
1:09
didn't exist yet.
1:11
But just because both Intel and AMD seem to agree
1:15
that their processors will last
1:17
at least through their warranty period at that temperature,
1:21
doesn't mean having it there is a great idea.
1:24
The hotter an integrated circuit runs,
1:26
the more power it will consume
1:28
and the shorter its lifespan will be.
1:29
And furthermore, when your CPU does approach its limit,
1:32
you can experience greatly reduced performance.
1:36
That throttling mechanism.
1:37
That I alluded to before.
1:39
So if your only goal is not sacrificing performance,
1:43
then temperatures that don't exceed 90 degrees,
1:46
it's honestly a good spot to start
1:48
with 65 to 75 under full load
1:52
being the conventional wisdom target,
1:54
as well as contributing
1:55
to a quieter computing experience overall.
1:58
So finally getting to our PC then,
2:01
in here, we've got an RTX 2070
2:04
and an Intel Core i7-9700K.
2:06
But since any decent cooler
2:08
can keep the stock 95 watt 9700K at bay,
2:13
provided you don't live in the Sahara, of course,
2:15
we cranked it up to a blistering five gigahertz
2:18
on all eight cores at a voltage of 1.33 volts,
2:22
bringing it up to 160 watts.
2:24
Now, we definitely need something a bit more robust.
2:30
Or do we?
2:31
This overclock was actually achieved
2:32
using just a Noctua NFU12S, a mid-range air cooler,
2:33
coming from Intel.
2:34
And that's what we're going to do today.
2:35
We're going to test it out.
2:36
We're going to test it out.
2:36
We have a 10 gigahertz controller coming in at just $60.
2:39
And with just one fan,
2:40
it was able to keep us at a max of 84 degrees.
2:43
Now, that is a little toasty.
2:45
And with our fan at full blast,
2:47
it was a little loud,
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at least by Noctua standards, at 45 decibels.
2:52
So well, now it's time to go water cooling then, right?
2:57
Maybe, but not until we've adjusted our test setup.
3:02
The thing is, 43 decibels is clearly audible
3:06
and bordering on annoying to have right next to your head.
3:09
But for context, the average office is 50 decibels.
3:14
So because noise is just as important
3:17
as cooling performance,
3:19
we had to create an environment
3:20
where we could properly evaluate both.
3:23
Okay, so why don't you show me what you've done here?
3:26
Yes, welcome to my room of quietness.
3:28
This used to be an office, you know.
3:31
Yes, but now it's uncomfortably silent.
3:35
So we know this is kind of ghetto,
3:37
but it works via the same principles
3:40
as our recent server room sound deadening video.
3:43
Basically, if you take a bunch of loosely packed
3:48
permeable mass and you put it all around
3:52
where you're trying to block the sound,
3:55
you don't get any standing waves.
3:57
It ends up absorbing a lot of the sound
3:59
that's trying to come in
4:00
and preventing any reflections and bouncing.
4:03
So basically,
4:05
because we can easily control the HVAC,
4:07
this room has its own dedicated thermostat.
4:10
And because we've got all these beanbags set up,
4:12
we're able to achieve, what was it?
4:14
26 decibels.
4:16
A 26 decibel noise floor in here.
4:18
That means that we can comfortably measure devices
4:22
like this computer that are not much above 30.
4:26
Now this computer has been modified
4:28
from our original configuration a little bit.
4:30
So it's running four of Noctua's NF-A12X25FLX fans.
4:33
So it's running four of Noctua's NF-A12X25FLX fans.
4:35
So it's running four of Noctua's NF-A12X25FLX fans.
4:35
So it's running four of Noctua's NF-A12X25FLX fans.
4:35
With their ultra low noise adapter
4:37
coming off the power supply.
4:38
So these are at just 900 RPM.
4:40
That power supply is a prime fanless titanium
4:44
from Seasonic unit.
4:45
So it's not making any noise.
4:47
The graphics card, there's not much we can do.
4:50
Your system's gonna have a graphics card in it, but-
4:53
It does have a silent mode.
4:54
It does have, oh, it does.
4:55
Oh, the fans are off.
4:56
It has a switch on it.
4:58
Perfect.
4:59
Thank you, ROG Strix.
5:01
So what this means then is that our only variable
5:05
is our CPU cooler.
5:06
Now, some of you have probably noticed
5:09
that the spot where we mounted the radiators is in the top
5:11
because we've got case fans in the front here.
5:13
And that was for a reason.
5:15
So on the one hand, yes,
5:17
drawing in fresh air for your radiator
5:19
is going to give it an advantage
5:21
versus drawing in warmed up air
5:23
and exhausting it out the top of the system.
5:25
However, what we found was that the disadvantage
5:28
from an acoustic standpoint
5:30
of having it right there in the front of the case
5:33
was much greater than the advantage
5:35
it gained from having access to fresh airflow,
5:39
especially because you guys got to consider,
5:40
this is not exactly a little tiny mid-tower chassis.
5:43
We've got three intake fans.
5:45
So the ambient temperature inside the case
5:48
is really not that much warmer.
5:49
So to keep things as real world as possible,
5:51
we're using the blender classroom test.
5:53
So that takes about 17 minutes
5:55
and that's enough time to heat up most AIOs.
5:59
And we were having issues where the whole room
6:01
was heating up two to three degrees.
6:04
And given the fact that we had to do that,
6:05
given that's more than the variation
6:07
between all of our coolers,
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we had to have HVAC on and the door open
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and then run in at about 16 minutes,
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turn the HVAC off, measure the acoustics and boom.
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So with that out of the way,
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we're ready for the results.
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That we are.
6:25
Are you excited?
6:26
I actually am.
6:28
Which one of these do you think is the best?
6:31
Cooling, purely cooling.
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Am I supposed to play devil's advocate or am I?
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Actually guess.
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Actually guess.
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I would guess that it's gonna be
6:42
the triple 120 millimeter red
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from a sheer mass and surface area perspective.
6:49
Not even in second.
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This guy here.
6:52
Really?
6:53
Yup.
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Which one do you think?
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So hold on.
6:55
We're talking raw performance at a given noise level.
7:00
Just raw performance.
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Straight up raw performance.
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Yup.
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This beats this.
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Yup.
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78 degrees, 81.
7:10
Wow, that's not even that close.
7:11
No.
7:12
Okay.
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And guess what sound level they were both at then?
7:18
Okay, this one right here was at 36.
7:22
Okay, 36 decibels?
7:23
Yeah.
7:25
Okay.
7:26
I would say this with only two fans
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is gonna have to be a little louder, 38.
7:30
34.
7:31
Really? It's quieter too.
7:32
Yeah.
7:35
And the worst part is that this right here.
7:39
Yeah.
7:40
It performs the 360.
7:43
And isn't the 360 the one that comes
7:45
with their new redesigned cold plate?
7:47
Yeah.
7:48
So the Ace Attack one,
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it's only a two degree difference,
7:52
but also like 79, 81.
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So.
7:57
So it's quieter as well.
7:59
Yeah.
8:00
And this right here, garbage, 86 degrees.
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This guy fared pretty well.
8:06
So.
8:07
Okay, well now let's talk price to performance then.
8:09
So we know this is our least expensive offering.
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This was like our mid-tier air cooler.
8:12
Yeah.
8:14
This is probably more like 80 bucks, right?
8:16
70 bucks.
8:17
The one that I really don't understand
8:19
is how this performs so well.
8:22
I guess this is really a testament
8:23
to how well heat pipes perform then.
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And also just Noctua, like they just kill it.
8:30
They know their shiz.
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But if you think about it, like yes,
8:34
water transfers heat very quickly,
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but heat pipes are also fluid heat transfer.
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So this is actually phase change cooling on a certain level.
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So then one point of clarification though,
8:45
do you think this is unique to Corsair's AIOs?
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Like, are they just bad?
8:49
No, I think they're pretty good.
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They're just like the largest company for AIOs
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and they all use basically the same design.
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So it's the most representative.
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Right.
9:00
Cause that's what people are probably gonna buy.
9:01
I'm gonna get you to take these two away since they're done.
9:04
So things don't look great for our water coolers,
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but there is more to the story than performance.
9:09
And performance, noise levels and price to performance.
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Let's run through some more pros and cons.
9:16
So one big problem,
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an additional problem for water coolers is actually the pump.
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Not only does that add additional noise and cost,
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it also adds a point of failure and a nasty one too.
9:29
Since not only are pumps more likely to fail than a fan,
9:32
but when they do, it's more catastrophic for your cooling
9:36
and it's harder to detect.
9:37
Now, if your CPU fan dies,
9:39
then you can probably see that it isn't spinning
9:43
and then slap a case fan on there until a new one arrives.
9:47
With a pump,
9:48
you better hope that you have your software monitoring
9:51
enabled and then when it does bite the bullet,
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you pretty much just need to pony up for an entire new unit.
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An unattractive prospect since AIOs, like I said,
10:00
extra components tend to be more expensive than heat sinks
10:03
with similar performance.
10:05
But that doesn't mean that AIOs don't have
10:10
some advantages.
10:12
Because it's full of water,
10:14
an AIO has greater thermal mass than a heat sink.
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That means that even though after a long load,
10:21
its performance might not be as impressive,
10:24
during short bursts, like while your CPU is turboing up,
10:28
that extra heat can be absorbed then dissipated later
10:32
without such stark swings in temperatures.
10:35
Also, if you regularly move your PC,
10:38
like to LAN parties in search,
10:40
transportation is arguably much safer with an AIO.
10:44
I mean, we are talking for this guy,
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12 points of contact versus just two for this.
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Big bulky air coolers have a lot of weight
10:56
hanging directly off of your CPU socket,
10:59
which in some extreme cases can actually lead
11:02
to motherboards bending or even breaking.
11:05
Now, this isn't as much of an issue with brands
11:08
that have good mounting hardware,
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which is one of the reasons
11:10
that we so strongly recommend Noctua.
11:13
But even with Noctua mounting,
11:15
if I needed to entrust my PC to an airline
11:18
or a parcel carrier, I would equip it with an AIO.
11:23
Another good point for AIOs is the coolness factor,
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not coolness for your CPU,
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or even for your motherboards VRM,
11:30
which can benefit from incidental airflow
11:32
that bleeds away from the heat sink.
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But I mean, coolness for showing off your PC.
11:37
Now, naturally this comes down to personal preference,
11:38
but I mean, coolness for showing off your PC.
11:39
But I mean, coolness for showing off your PC.
11:40
Some people really like the look of big air coolers.
11:43
Yeah.
11:44
Thank you, Alex.
11:46
But most of the time,
11:47
it's easier to get a cleaner overall look
11:50
to your build with water.
11:52
Now, one thing we haven't mentioned yet
11:54
is custom liquid cooling.
11:56
With a top of the line block from EK or Alpha Cool,
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a huge radiator and a D5 pump,
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you can get measurably better performance
12:05
than what is possible even with the beefiest of air coolers.
12:09
The thing is, at that point,
12:11
it isn't really a fair comparison anymore,
12:13
since a custom water cooling setup
12:15
is only for very advanced users,
12:17
requires regular maintenance,
12:19
and is incredibly expensive.
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Like just the CPU block alone
12:23
can cost more than our NHU 12A.
12:25
That's not to say custom water cooling isn't awesome
12:28
and that we don't love it for ourselves.
12:30
It's just not the kind of thing
12:32
that we're comfortable recommending to people who,
12:35
well, enjoy using their computer as opposed to, you know,
12:35
well, enjoy using their computer as opposed to, you know,
12:39
tinkering with their computer.
12:41
So thanks for watching, guys.
12:42
If you just liked this video, you can hit that button.
12:44
But if you liked it, hit like, get subscribed,
12:46
and maybe consider checking out
12:47
where to buy the stuff we featured
12:49
at the link in the video description.
12:51
Also down there is our merch store,
12:52
which has cool shirts like this one.
12:56
Bottles, there's some.
12:58
And our community forum, which you should totally join.
13:02
Nope.
13:05
You know what's funny is I remember back when
13:08
these 120 millimeter Asetek units first launched,
13:11
like 10 years ago or whatever it was,
13:13
the initial reviews for the Asetek LCLC,
13:16
go find reviews for it, overwhelmingly negative.
13:20
But then when the Corsair H50 turned up,
13:24
which was literally exactly the same product
13:26
with a different fan on it, the reviews get positive.
13:30
And I'm not accusing, I know the people at Corsair very well.
13:34
I know for a fact they didn't pay off anybody.
13:37
But like, it's just funny how a brand can,
13:41
like the brand name and brand loyalty
13:43
might subliminally influence people.
13:45
Like with the Asetek ones, people would be like,
13:46
yeah, it's not great.
13:49
And then with Corsair, they'd be like,
13:50
yeah, it's like, it didn't perform as good,
13:52
but like, here's all these other benefits.
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I don't know, it's a funny thing.
13:57
Ha!
13:58
Ha!