NZXT H3 Flow review - a sleek, compact PC case for a great price

NZXT might be best known for its ATX cases and large liquid coolers but it has also dabbled in smaller form factor options with some success, and its NZXT H3 Flow is its latest mATX effort. Not only is this new PC case compact compared to an ATX case and possessing of a super clean look, it also costs just $60 and, while it's small, it can house two AIO liquid coolers and has ample clearance for tall air coolers along with very large graphics cards too.

Arguably, the best PC case options for mATX systems are ones that aren't too much larger than the motherboard, as otherwise you may as well just get a full-size case. In that sense, the NZXT H3 Flow isn't the most standout option, as it's only an inch or two smaller than typical ATX cases. However, it is still technically more compact and yet doesn't compromise on the cooling and components you can fit inside.

Such a compelling combination means we were very keen to put this case to the test to see what, if anything, its $60 price has meant in terms of cost savings and compromises. Is it worth considering compared to popular competition such as the Lian Li A3 mATX or Phanteks XT M3? Read on to find out.

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Specs

Features

The key is in the name here, with the H3 Flow featuring perforated mesh sections on five of its six panels for high overall airflow. The biggest of these is the front panel with a near edge-to-edge mesh sitting in front of two fan mounts that can house either a pair of 120mm or 140mm fans as well as 240mm and 280mm AIO liquid coolers. These dictate the graphics card length limit too. This measurement stands at 377mm with no front fans, falling to 352mm with front fans installed or 317mm with a 30mm-thick radiator and fans. As for CPU coolers, up to 170mm-tall options are supported.

The panel, which is both decorative and acts as the dust filter for this section, is removable by just pulling it off. This is easy to do and gives you access to the fan mounts behind. There are no front fans included as standard and in fact only a single rear 120mm fan is included to keep the cost to a minimum. The roof panel also offers a home to a pair of 120mm or 140mm fans, but depending on your motherboard's heatsinks, you'll likely be limited to a 240mm radiator here.

The roof panel is fixed and includes a removable magnetic dust filter, which once removed gives clear access to the fan mounts. There are two more 120mm fan mounts in the PSU cover, with screws in the box included to make use of these, although depending on your motherboard's GPU slot location and graphics card thickness, these may not be usable.

The included fan is an NZXT F120Q (CV), which a quick Google search suggested had a potent 1,750rpm peak speed, but the one included here peaks at just 1,350rpm, which is quite average. Combined with the multiple mesh panels, negative pressure is the dominant feature here. If you want to improve cooling, the logical spot for an extra fan would be in the front pointed at your CPU cooler, but we'll see the benefit of this in a minute.

The side panels are both tool-free, with the main glass panel sitting in the top three quarters of the case above the large mesh section on the side and being held by push-pins.

The front panel connectors are minimum with just single Type-A and Type-C USB ports, although the latter does support USB 3.2 Gen 2×2 with speeds up to 20Gbps. Your motherboard's Type-C header needs to support this too if you plan on plugging in an external SSD that offers the same speed. One omission here is an audio jack, so you're out of luck if you want to hook up your headset or microphone to the case front panel. You'll need to use your motherboard's own port or a USB-based audio device instead - whether that's a USB headphone amp or a wireless gaming headset with a USB dongle.

If you have 2.5in SSDs or 3.5in hard disks you want to use, there's space for up to three of the former or one of the latter here. There's one dedicated 2.5in SSD mount on the rear of the motherboard tray and a shared mount underneath the PSU cover that supports either two 2.5in devices or a single 3.5in hard disk.

Design

This is a great-looking case, with our white sample looking particularly clean and smart, although if you prefer black cases, there's an option for you too. It feels well-made and, despite the use of push-pin panels, none of these seemed to rattle. Its 5kg weight comes largely from its glass panel and steel construction, the latter of which you'd expect at this price, rather than more expensive aluminum.

Another omission here that you'd expect to see on more premium cases is rubber grommets in the cable routing holes. This means any PC's built into this system will particularly benefits from ensuring your cables are neatly secured, to prevent them rubbing on these unprotected openings.

Cables may also pose an issue for owners of rear connector motherboards such as MSI Project Zero or Asus BTF, as the clearance behind the motherboard tray for routing cables these these systems is very tight. Again, you'll need to spend a bit of extra time here clompared to cases with more generous cable routing areas, and it's likely why this side panel uses thumb screws rather than push-pins, to remove the possibility of the panel being pushed off by the cables.

Thankfully the case is otherwise easy to work with, whether you're building an air or liquid-cooled PC. It also has plenty of space under the PSU cover to stow cables and thanks to easily removable panels and dust filters, is easy to maintain too. The only snag we hit in building the PC is that there's no mention of PSU orientation in the manual or product webpage. There's no vent underneath and the PSU sits very close to the base of the case, so we'd be inclined to have its fan pointing upwards.

Another factor to consider is that the dimensions of this case mean it's not the most compact mATX case around. At 15.75in (40cm) tall, it's only an inch or two shorter than smaller ATX cases. The depth of 15.31in (39cm) is a little more compact, but to maintain good CPU cooler compatibility, NZXT has made the case nearly 9in (23cm) wide.

Performance

To test the NZXT H3 Flow, we installed our standard test system into the case to then test it for cooling capability and noise levels. Our standard system consists of an AMD Ryzen 7 9800X3D CPU, 32GB DDR5 6000 RAM, an Asus B850M-Plus WiFi motherboard, 1TB Samsung 990 Pro SSD, an MSI RTX 5070 Ti 16G Ventus 3X graphics card, and a Cooler Master Hyper 212 Black CPU cooler.

To maintain consistency between cases we fix the case, CPU, and GPU fan speeds. For the CPU, we normally find our cooler's fan will hit maximum speed under load in some cases, so we maintain it at full speed. We do the same with the case fans.

For RTX 5070 Ti, it typically peaks at 60-70% speed when left to its own devices, so we lock its fans at 60% to prevent them spinning up and skewing the results in poor performing cases. To test the GPU, we've used Metro Exodus: Enhanced Edition over multiple back-to-back benchmark loops. For the CPU, we load it at 100% using Prime95.

The CPU temperature of our Ryzen 7 9800X3D reached 81°C, which is perfectly acceptable and even impressive given the lack of any front fans. In fact, adding one pointing at the CPU cooler only dropped the temperature by another 2°C, so overall airflow clearly isn't lacking here. The GPU temperature of 71°C was also decent given how quiet the fans are at 60 percent speed, likely thanks to the well-ventilated front and side panels, as well as the ventilated PSU cover below the GPU fans.

Allowing the fans to do their own thing resulted in a noise level of 40 dBA during the CPU stress test, and it was very clear the case does allow a fair amount of noise to escape, which is expected given the amount of mesh it has. Forcing the noise level down to a more reasonable 35 dBA on our sound meter saw the CPU load test rise to a very toasty 93°C while the game test saw another 12°C added to the GPU temperature. It's clear that to have a quiet system in such a porous case will require large heatsinks or liquid coolers.

The NZXT H3 Flow's price is $60 and we feel NZXT has hit the nail on the head here. It's a somewhat basic case with few frills and just one 120mm fan, but it looks good, has zero issues with build quality, has excellent cooling potential whether you prefer air or liquid, and is super easy to build in and maintain too. The fact it has black and white options means it offers enough versatility to suit most build styles too.

There are alternatives for similar prices such as the Lian Li A3-mATX and Phanteks XT M3, but these don't include any fans as standard, while other options often include RGB lighting and cost noticeably more. We'd liked to have seen an audio jack on the front panel, and ideally have 360mm AIO liquid cooler support, but 280mm liquid coolers offer nearly as much cooling and are a sensible choice for a build of this scale.

Verdict

For $60, NZXT hasn't really put many feet wrong here as the H3 Flow is a good-looking, sturdy, well-thought-out case that manages to offer loads of room for large graphics cards as well as multiple mounts for liquid coolers and additional fans, plus its CPU cooler clearance is excellent. This is an affordable, compact case that can easily house a high-end gaming PC.

There are a few drawbacks, though such as the lack of an audio port on the front panel, even if the Type-C port impressively offers USB 3.2 Gen 2×2 20 Gbps support. We'd also have liked to see rubber grommets in the internal cable routing holes and a little more clearance for rear-connector motherboards round the back too. For an mATX case, it's also not particularly compact, but it still just about stays smaller than typical ATX cases.

Overall, then, this is an excellent allrounder for those looking for a PC case that's compact but not quite as limiting as a mini-ITX option. Of course, the mATX form factor has limitations of its own, such as a weak choice of high-end motherboard options, but that's a fair compromise for anyone considering buying a $60 PC case. Some reasons to consider alternative cases are to allow for housing 360mm liquid coolers, if you particularly want more glass panel, or perhaps if you want out-of-the-box RGB lighting. Otherwise, the H3 Flow ticks most boxes and is excellent value.

If you've decided this is the case for you, why not complete you system by checking out our best gaming motherboard and best CPU cooler guides.