I always thought that when it comes to water cooling more is automatically
better that is to say if one radiator is not enough you can just add another one
or another two to get better performance well it seems that I've been water
cooling incorrectly for years or at
least that's what Coursera leads me to believe like what how could that
possibly be that adding more radiators wouldn't help I just can't believe that
to find out exactly what they said to me you're gonna have to sit through the
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when we showed our concept cooling system for our hack Pro 2019 with a
front intake radiator and a rear exhaust radiator Corsair emailed me to say that
according to their simulation data that second radiator would be at best
pointless and could even make our cooling worse because it adds more
airflow resistance and because I mean think about it the second radiator can't
cool water with hot air from inside the
case I ignored them and then when we showed off Jake's custom minecraft
server that used not one not two but three thick alpha cool radiators stacked
against each other with layers of Noctua eighty millimeter fans in between course
I reached out again to admonish me for
water cooling wrong the problem is like guys my experience tells me that
stacking radiators works great or at
least I thought it did I've never done a side-by-side comparison it makes sense
though like you would think that doubling the surface area radiating heat
away from the system must lead to if not
double than at least significantly better performance but guys turns out
it's not that simple in order to dissipate heat in a water cooling system
there needs to be a difference in temperature across the materials in your
heat exchanger in this case that's the ambient air which is cooled and the
water which is warm from your components and then this is really important the
greater that difference in temperature the more heat can be exchanged and the
thing is because modern radiators are so
efficient as Corsair if the water temperature is let's say 40 degrees
under load we can bet that the air coming out of that rad is going to be
just below that meaning that by the time it picks up some extra heat from air
cooled components like motherboard VRMs it's not gonna have any heat capacity
left to pull heat from a second radiator
that it's going through that kind of makes sense but I wasn't ready to give
up yet so to determine once and for all
if adding a second rad is useless we decided to build a test rig
call and got to work and piece together there it is that little tower sporting
an RTX 2080 TI and Intel's 9900 KS or as
I like to call it my little furnace together this pair can draw a little
over 400 watts of power under a synthetic load and all that heat is
going right into our water bt-dubs guys
if you like water loops get subscribed we're planning to water cool a gaming
chair and you're not gonna want to miss that if you get warm in the summer so our first test is to establish a
baseline with a single 240 millimeter rad upfront pulling air in to be
exhausted out of the top of the case with a second pair of matching fans the
system stays cool enough not to thermal throttle but it's also obvious that our
radiator is up against its limit so according to my common-sense PC building
wisdom this system would have looked like a perfect candidate for just
throwing another radiator at the problem with that out of the way then it's time
to plumb up our second rad in series and put it in the top of the case with more
or less the same fan configuration now we did end up having some RAM clearance
issues requiring us to put the fans on top of the case but that should not
negatively impact our data the important thing is that the radiator is still
inside the case exposed to all the other heat sources that are in there now for
the moment of truth our stress test was designed to hit both the CPU and
graphics card with fir mark while logging all the pertinent data using
hardware info that means not just temperatures but also power consumption
and clock speeds in each scenario the
system was allowed to hit a steady-state and then we stopped the loads and let
the system cool back down to our idle temperatures let's look at the numbers
popping right into the GPU temps the redline is with the single rad and the
green line is with our dual rad setup not only did our dual rad setup take way
longer to reach its max temperature it also ran way cooler about 20 degrees
cooler in fact so that's it Corsair your
myth is busted and a video I'm out just
kidding we did our due diligence and check the CPU as well to make sure that
both loops were actually experiencing the same load and they were both
scenarios had the CPU clock between 4.5 and 4.6 nothing out of the ordinary
there and our power usage looked nearly
identical as well so then why didn't our
results match Corsairs claims to be clear guys I'm not saying that they're
CFD analysis or their real-world testing is wrong or that what they said doesn't
make sense and let's remember as well
they didn't actually critique this exact build all I'm trying to say is that this
kind of simulation rarely translates perfectly to the real world and also
that you should go delta-t sir calm ok no that was an aside so our working
theory is that the openings in the case at both the back and the bottom allowed
for some fresh ambient air to come in and mix with the hot air before being
pulled up through the second read now if we had sealed off every potential air
leak it's possible we would have seen something closer to Corsair simulation
but as far as we can tell that's just not a true representation of the real
world I mean nobody would do that another thing to consider is that every
system is a little different fan orientations fan speeds radiator
placement pump flow rates case designs all these things will affect how a
cooling system works as we've seen with the minecraft server and the hack probe
sometimes the truth of the matter is you've just got to work with the space
you've got and we also did another sanity check we had Jake remove one of
his stacked radiators which ended up resulting in a 5 degree increase in
temps under load that's another proverbial nail in this coffin now I'm
sure that in some rare cases it could actually be a negligible or a bad thing
to add a second radiator but a blanket statement saying that stacking rads is
bad just isn't even nearly true and you
should really look at your particular use case and evaluate for yourself if
you can so the moral of the story here is take everything with a grain of salt
including what I'm saying right now do your own research and do a little
benchmarking on your phone on your phone on your own it's easy free fun and can
tell you loads about how to make your system work best for you so that's it if
you guys want to check out some more benchmark related videos why not take a look at the video we did last year about
finding out if your gaming rig is bottlenecked we're gonna have that
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