CPUs run hot. So hot that they would destroy themselves if it weren't for built-in protections
that slow them down. But we don't want to slow down. We want to go fast and thus nerds are willing
to spend hundreds of dollars to keep their CPUs cool. But what if there's a whole other side
of cooling that no one's talking about? The back side, why not put a cooler there as well?
So we did. Before you furiously comment saying, cooling a CPU from the back doesn't work, there's too many layers of stuff between the CPU and the
cooler for it to be effective. Well take a look at this footage. That is heat on the back of the
motherboard and there's enough that removing it might actually make a meaningful difference.
So does it? And if it does, is it easy or cheap to do? Well that depends. Not until after this
segue. To our sponsor. The simplest way to cool your CPU from both sides is to just
point a fan at the back of it and that's been done before. My first PC case was the Antec 302,
which had a mount for a fan right behind the motherboard tray. Did I spend 30 of my high
school dollars on a Noctua fan to put it there? Yes. Did it do anything from what I remember?
Kinda. So first things first, let's see if Antec was cooking or not. Noctua has this handy magnetic
mount from their desk fan that we're just going to use just as a quick little preliminary test here.
We're seeing about a degree or two difference going from like 51 point something to more
closer to 50, 49.7 kind of area. And that lines up with the preliminary testing that we did
taking measurements from the CPU and hardware info. But we all know that proper cooling requires
contact. So let's see how easy or hard it is to mount a cooler on the back here. First things first,
any mounting design that we make will need to make sure that the CPU cooler on the front
isn't affected because spoiler alert, it's doing most of the work. And mounting hardware for CPUs
is made with relatively tight tolerances to ensure that you can get even contact across the CPU's
integrated heat spreader. And pretty much every part of the mounting hardware plays an important
role, including the parts that go on the back of the motherboard, which are in our way. Let's get rid
of it. And you know what else is in our way? The Intel socket backplate that holds the CPU
retention ARM on the front. And that also prevents our second cooler from making direct contact with
the back of the motherboard. So not only can we not get away with using out of the box CPU cooling
parts for this, we're going to have to remove the backplate as well, which means that we're going
to need to make a custom backplate. Yes. Originally, what I was thinking of doing is we could probably
just modify the original backplate to add the cooler onto the back. However, as you can notice,
there isn't really a whole lot of material on the ends to put the bolt holes through. I'd basically
be drilling right along the edge here. So we're going to have to make a new one out of metal.
Well, that's one thing I noticed. Oh, is that going to be a problem? They probably put this
so there's a small thin layer insulation layer to probably make sure just in case
that none of these traces or contacts. Oh yeah, because there's definitely open views there.
So we plain just won't be able to get the same degree of contact on the back as we have on the
front. First of all, we're on the wrong side. But second of all, this is not a flat surface like
the cold plate on your cooler or the IHS on your CPU. There's a bunch of tiny electrical components
that are going to prevent this cold plate from sitting flush with the back of the motherboard.
What are we going to do about that? Well, we're going to need a cushioning layer that's a lot
thicker than your typical thermal paste, like this one millimeter pad. Sadly, it has a worse
thermal conductivity than any thermal paste. But hey, it's much better than air, which is what
the fans are working with. So I'm just going to estimate it because like, is this got to be good
enough? You know, that's what I always say is just got to be good enough. We decided to go with a
mechanism that's just mounting into these corners that are already part of the Intel bracket because
it just makes our lives easier. To mount in here, we had to make some custom length screws because
I don't even actually know exactly what these holes are for on the Noxua coolers because I've
never used them. I'm assuming it's compatibility with much older hardware, but I've never actually
had to use them. So now I do. And it's what an exciting time for me. A new experience. Thankfully,
there's Robertson screws in the precision screwdriver kit, which has an adapter that lets
you lose any of those precision bits with the LTD screwdriver. Technically, the length of these
screws should mean that nothing actually will screw into the motherboard, but there is a chance that
like things can bow and bend a little bit. So I am going to be careful. I'm kind of trying to stop
when I feel resistance out of just sheer terror because I am legitimately worried about this
board existing. So let's, let's boot. If this seems simple, it's because Justin did all of the
hard work, honestly. I mean, looking at it right now, we're still looking fine. It's not better.
It's not worse. This is kind of interesting. So when we're looking through the thermal camera,
we can see that our front CPU cooler is just much, much warmer overall than our back CPU cooler,
which implies that it's moving away a lot more heat to be expected. But honestly, it feels like
we haven't done much because the base of our CPU cooler is 20 degrees. So I don't think it's,
it's doing much at all. So why doesn't the cooler perform better? Well, the motherboard is acting as
an insulator, which slows the rate of heat transfer. And it doesn't matter how thermally
conductive our CPU cooler or our thermal pad is, it can only remove the heat that reaches the other
side of the motherboard. Think about it like this. It doesn't matter how many lanes your highway is
if everyone has to file through the same single lane bottleneck. Support public transit. This cooler
can only pull away as much heat as it's being given. But once you pull all of the heat away,
you're going to be rate limited by the motherboard. So it doesn't matter how much extra cooling power
you put in here unless you decide to go sub zero. And if you're going to go sub zero,
just put it on the front. Don't put it on the back. I'm just going to take the fan out. I wonder
if it will even like, the cooler will even saturate. Like that would be a good indicator
if, if this thing is actually doing anything. 21.3. It's going up very slowly. So it is actually,
we're transmitting some heat away, but you know, it's going to make this heat up faster
as if I just touch it with my hand. Let's compare that to running the front without the fan. So
we're looking at it right now. It's sitting at 27 degrees. Now Reese is going to hit
Cinebench. And we're going to see how quickly this thing heats up. 28, 26, 29, 30. It's like,
it took us like literally minutes to go up a degree before. And this is climbing
a degrees per second. And eventually it will start getting to the point where it's probably
thermal throttling. This just illustrates how much more important this is than whatever we're
doing on the back. Keep watching, please. We decided to use our environmental chamber to
have a perfectly controlled temperature for the most precise of results. But when we tested in
there, every permutation of our system performed the exact same. Back panel, back fan, back cooler,
stock cooler, it did not matter. Was all of our preliminary testing wrong? No, it's the environmental
chamber who was wrong. To maintain temperatures within a tenth of a degree, the chamber needs to
constantly blow conditioned air. And that conditioned air blowing was enough to cool the
motherboard on our control system, which means that we saw no improvements on our cooled system.
And that blows. We needed a more realistic airflow scenario. So we found a spot in our
office that was roughly equidistant from a bunch of ventilation. We set the room temp to a tight
22-ish degrees and tried again. And would you look at that? With the custom back plate and a fan,
we see CPU temps drop one to two degrees. Heck yeah. And with our cooler mounted to the back,
we see a further improvement of one or less degrees. It's not nothing, but it is almost nothing.
Oh, and we've kind of been neglecting to tell you about the results that make this whole endeavor
look even more foolish. When we compare CPU temps with our front mounted cooler on its
stock mounting hardware, instead of our custom back plate, it performs better than our back
mounted cooler setup. So all the haters at the start of the video who said this won't work,
shut up. It does work. It just works poorly. Maybe you could get better performance out of
a more precise custom mounting mechanism. But why bother when you can just do this?
Or maybe you could just segue to our sponsor. Thanks for watching. What do you think? Was
there something that we missed, something that you could have done differently? Let us know in
the comments. And if you liked this video, why don't you watch a cooling solution that did work
like our AC cooler?