We're starting to see a trend of high positive pressure in cases, heavily focused on intake
fans, but this goes against the last 50 years of cooling electronics.
That is, negative pressure with a focus on exhaust.
Howdy howdy guys Ponchato here, and today we'll be taking an in-depth look at the CMT520
Plus from FSP, and also doing some empirical testing of positive pressure cooling vs negative.
The CMT520 Plus has a cooling layout very common to modern case design with three fans
up front and one in the back, so it's a good benchmark for comparing airflow pressure styles.
My guess is that negative pressure will be somewhere between "a little" and "a lot" cooler
than positive pressure, but we'll find out for sure with the benchmarks later in the
video.
First, let's talk a bit about the case.
The CMT520 Plus is one of FSP's latest case and runs right along the edge between mid-tower
and full-tower.
It's almost 500mm long, 215 wide, 510mm tall, and a very sturdy 8.5 kilograms.
In American that's 19.5 inches long, 8.5 wide, just over 20 tall, and almost 19 pounds.
It can fit motherboards up to extended ATX and has 8 expansion slots, all of them replaceable
with a screw rather than the bend and snap style.
On the bottom you have the easy access power supply filter, which can be removed for cleaning
without tipping the case, and four feet with foam pads.
The foam on the feet offer a moderate level of grip and will help isolate your case from
desk, which should help prevent any annoying resonance.
In terms of materials and build quality, the case is mostly steel save for two tempered
glass panels - one on the side and one in front.
The front tempered glass is built into a plastic front panel which is actually kind of flimsy.
It's also not terrifically easy to remove, which a bit of a letdown given the CMT520's
price of $130 USD.
Other than the plastic on the front panel though, the rest of the case feels solidly
built and I couldn't find any problems with it flexing or bending.
Looking at the front panel I/O, we have two USB 2 jacks, microphone and headphone, buttons
for power, reset, and cycling the LED lighting styles, and two USB 3 ports.
Also kind of interesting is the power and hard drive activity LEDs are both built into
the power button, and pretty atypical colors; the power LED is aqua and the storage LED
is pink.
That's pretty unusual.
And just as a quick note, the CMT520 Plus is basically identical to the CMT520 except
the Plus includes addressable RGB fans.
Other than the fans, the two cases are pretty much identical.
The tempered glass side panel is held on with 4 thumb screws, typical for most TG panels.
Looking inside the case you're greeted with quite a bit of space.
The power supply shroud is actually two parts: a solid metal side panel with a cutout to
show off your power supply, and a dark tinted acrylic plate with magnetic strips that goes
on top.
It's a highly reflective surface, so it does add a cool effect to the case aesthetics.
Under the power supply shroud you have space for a 200mm PSU and the two bay hard drive
cage.
The tool-less drive caddies pull apart in the middle to fit a hard drive and then slide
back into place, or you can mount 2.5" SSDs to the caddies if you're going the solid state
route.
In addition to the drive bay you have two SSD mounts on the front of the motherboard
tray, and two more on a removable bracket on the back of the motherboard tray.
In total the CMT520 can fit either four SSDs and two hard drives or six 2.5" SSDs.
Looking at the motherboard tray you have a ton of cable routing holes all the way around,
which unfortunately do not include grommets.
The CMT520 can fit CPU coolers up to 163mm tall and GPUs up to 423mm, so pretty much
anything available today will fit in this case.
Looking at cooling, the CMT520 Plus comes well equipped with three 120mm intake fans
and one on the exhaust, all of which include addressable RGB LEDs.
The fans are powered and controlled by a box that's held to the back of the motherboard
tray magnetically.
The control box is powered with a SATA power connector - thank you for not using Molex
here, FSP - and includes an ARGB header to plug into your motherboard, if you plan on
using motherboard control for the LEDs.
The built in lighting effects look pretty good though, and have a wide range from solid
colors, fade, and the ever-present rainbow color wheel.
Now there is one trend I'm not happy to see, and that's a lack of RPM control - pretty
much every one of these fan control boxes I've encountered either runs the fans at a
fixed speed or only allows you to switch between 2 or 3 speeds.
In this case, the fans run at right around 1200 RPM.
While that is a reasonable speed to run case fans at, I would really like to see a method
for finer control.
The best thing I can think of is having a standard PWM fan cable from the control box
that you can plug into your motherboard, and then control all the fan speeds from the motherboard
just like you can the LEDs.
That would be awesome.
Someone please do that.
Speed control aside, the CMT520 does allow for ample air intake at the front with vents
along both sides and an offset to the tempered glass.
The front intake is completely unfiltered, which is something to keep in mind, especially
if you have pets.
If you keep your PC off the floor and don't have pets though, front intake filters aren't
all too important in my opinion.
In terms of total fan capacity, the CMT520 can fit three 120 or 140mm fans in front,
three 120 or two 140 fans on top, and one 120 fan in the back.
And for those of you going the water cooling route, the CMT520 may be exactly what you
need: it can fit two 360mm radiators, one in front and one on top.
That's a lot of cooling.
The top vents are covered with a magnetic dust filter and have two mounting rails side
by side.
I should add here: unlike front intake filters, top filters ARE useful because they prevent
dust from settling in your computer.
Given how huge this case is, the build process is very easy.
It comes with standoffs preinstalled for an ATX motherboard, so you'll need to move a
few if you're building with a microATX mobo.
After that the rear I/O shield pops into the back panel and you screw the motherboard down
on the standoffs - just make sure they're all lined up correctly before you crank down
on any of them.
The PCIe expansion covers are held in place with a sliding bracket, itself held with a
thumbscrew.
Once that's up you undo the screws holding the covers in place and they come right out.
The graphics card drops into the motherboard, you put the sliding bracket back down, and
secure it in place with the screws.
Now here's one thing I really do like: FSP uses a bracket to mount the power supply.
What that means is instead of trying to wiggle your PSU through the opening in the shroud
and then trying to plug in modular cables in whatever cramped gap is left, you instead
mount the power supply to a bracket, then slide it in, cables and all, from the back.
Yes, you have four more screws with this setup but the difference in ease of installation
is night and day, especially in smaller cases.
Anyway with everything installed and the cables cleaned up a bit, this case looks very nice.
The CMT520 has a ton of cable tie points on the back of the motherboard tray, but I do
have a few complaints: first, there aren't any toward the front of the case, which is
where most of the front panel cables end up getting shoved.
Second, every single cable tie point is vertical.
If you're just using zip ties or twist ties that doesn't really matter, but if you follow
the patrician's path and use velcro loops, having a mix of vertical and horizontal tie
points allows for easier and cleaner cable routing.
Now, these downsides are entirely eclipsed by the huge amount of space you have available
- space behind the motherboard tray is over an inch deep front to back, top to bottom.
And if you won't be using the hard drive cage, you can remove the caddies and have that entire
volume to shove cables as well.
Overall cable management in this case is easy and adaptable.
So there's everything about the case, but now let's address that question at the beginning:
positive pressure vs negative pressure.
First if you haven't heard those terms before, positive pressure simply means you have more
fans on intake than on exhaust; pressure in the case is "positive" or at a higher pressure
than the surrounding air.
Negative pressure is the opposite: more fans on exhaust, so pressure inside the case is
"negative" or less than ambient.
For many, many decades, almost every single electronic device with active cooling has
used negative pressure.
Whether a prebuilt computer, or a cable box, or a TV, almost all of them ever produced
have had mostly or only exhaust fans, not intake fans.
The general idea was that it was a more reliable way of getting hot air away from components
inside a cramped enclosure, rather than try to push it out from the front.
Back to the CMT520, with everything stock it has notably positive pressure: 3 fans on
intake, and only 1 on exhaust.
The negative pressure setup we're testing is with all 4 fans on exhaust, and I did that
by moving the 3 front fans to the top panel.
My test bench is a GTX 1060 3GB, a Ryzen 5 2400G cooled by a Cryorig H7 Quad Lumi, and
a Seasonic Prime AirTouch 850 power supply.
First we’ll look at noise from the case fans alone.
Somewhat unsurprisingly the CMT520's fans are the loudest I've tested because they run
at 1200 RPM, but the good news is that once you include the fans on the CPU and GPU, case
fans actually end up being only a small portion of the noise.
Interestingly here, with the three intake fans moved to the top, the noise level dropped
by 1 decibel.
That's not a massive decrease, but it is a curiosity.
Now here are the noise levels with the complete build.
Idle noise levels in the CMT520 are dominated by the case fans, which is why it's not that
much quieter than load, but the load noise levels are very similar to other cases I've
tested.
And the gap between the stock cooling layout and top exhaust disappears in this situation,
only a 0.1 dB difference which is well within the margin of error.
But now let's look at CPU temperatures.
With the stock, positive pressure layout, the CPU actually ran over 2 degrees cooler
than with all fans on exhaust.
Idle temperatures are also very low relative to cases with adjustable fan speed because
there's no way to slow down the fans at idle.
And finally we'll look at GPU temperatures.
This is where the differences really appear.
The graphics card vents a majority of its air out the back so it's less dependent on
the case fans at idle, but under load there's a fairly big gap between positive and negative
pressure.
In the negative pressure layout, with three fans exhausting out the top of the case, the
GPU ran almost 4 degrees warmer than with the stock layout and in fact the stock layout
had the lowest GPU delta of any case I've tested so far.
Gotta say, that's not what I expected.
So uh...
I was wrong.
Negative pressure isn't necessarily better and in fact, it was worse in this case by
several degrees.
That goes against most electronics cooling we've seen since, ever.
But, I will say, modern computer cases are a pretty far cry from a cable box or a Compaq
from 1997.
Cases like the CMT520 have, relative to older enclosures, massive intake and exhaust vents.
The space available inside, even fully loaded with a large aftermarket CPU cooler and triple
fan graphics card, is huge.
And above all, modern cases very rarely have just one fan.
It'll be interesting to see in future case reviews if this result, that positive pressure
outperformed negative, will show up consistently.
Pressure aside, the CMT520 Plus isn't perfect but it is a pretty sweet case.
The LEDs and styling look really good, there's plenty of room for cable management to keep
the interior clean and airflow unrestricted, and I just want to point out again how much
I like this power supply mounting system.
It's so nice.
I think a case like this is actually best for someone going heavy on liquid cooling.
It can fit two 360mm radiators.
There are not that many cases available that can do that.
And if you're putting together a build that requires two 360 radiators, the CMT520's price
won't be a big concern.
So if you're going for a high end, high heat build, especially if you'll be using liquid
cooling, the CMT520 Plus is well worth your consideration.
Follow the link in the description to pick one up for yourself.
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I wanna hear from you: is your PC set up with positive or negative pressure?
Let me know in the comments below!
Thanks for watching, I hope I helped, and I'll see you in the next video.
You know, I really should try out open loop cooling.
I've never done that before.
But then I think about bending the pipes and checking for leaks and dealing with the coolant
and all that and I'm just like, I don't want to anymore.
I'm fine with air cooling for now.
But it might be cool.