MSI MPG GUNGNIR 300P AIRFLOW Mid-Tower Review UK 2026

A PC case is the one component you'll interact with every single day, and yet it's often the last thing people think carefully about. After twelve years of building systems, I've come to measure a case's worth not by how it looks on a shelf, but by how it behaves at 3am when you're trying to route a 24-pin cable through a gap that's 2mm too narrow, or when you're checking temperatures after a stress test and wondering whether that mesh front panel is actually doing anything useful. The MSI MPG GUNGNIR 300P AIRFLOW sits in a price bracket where you're paying for specifics: proper mesh ventilation, vertical GPU mounting hardware included in the box, and a PCIe 4.0 riser cable that doesn't cost you extra. Whether those specifics translate into a case worth recommending is what two weeks of building and testing is for.

I built a complete system inside the GUNGNIR 300P AIRFLOW, running an AMD Ryzen 7 7800X3D on an X670E board with a 360mm AIO up front and an RTX 4080 Super mounted vertically. That's a demanding configuration, and it's exactly the kind of build this case is marketed at. Over the two weeks I ran thermal logging, checked clearances with a digital calliper, and paid close attention to the build experience from first panel removal to final cable tidy. The MSI MPG GUNGNIR 300P AIRFLOW Mid-Tower PC Case sits at the enthusiast end of the mid-tower market, and it has some genuinely interesting design choices that separate it from the crowd. It also has a couple of things that mildly annoyed me, which I'll get into.

Current pricing sits in the enthusiast mid-tower tier. You can check the live price below. With a 4.7-star rating across 57 on Amazon, there's clearly a lot of people happy with it. But aggregate ratings don't tell you about CPU cooler clearance or whether the cable routing channels are actually wide enough for a sleeved psu" class="vae-glossary-link" data-term="modular-psu">modular PSU cable. That's what this review is for.

Fan support is where the spec sheet gets interesting. The case ships with four 120mm fans pre-installed at the front as intake, plus provision for three additional auxiliary fans. Total fan mount capacity across front, top, and rear positions supports up to 420mm of radiator at the front, 360mm on top, and a single 120mm exhaust at the rear. The included fans are MSI's own units, and while they're not the highest static pressure fans on the market, they move reasonable airflow at moderate noise levels. The PCIe 4.0 riser cable is included in the box, which matters because a decent PCIe 4.0 riser cable bought separately typically adds another twenty-odd pounds to your build cost.

Weight comes in at around 9.5kg without components, which is on the heavier side for a mid-tower but reflects the E-ATX-capable chassis dimensions. The tempered glass side panel is 4mm thick, which is good. Some cases at this price point use 3mm glass that flexes noticeably when you press on it. The GUNGNIR 300P's panel feels solid. Dust filters cover the front intake, the top, and the PSU intake at the bottom, which is a proper set of filtration points rather than the token single filter you sometimes see on cheaper cases.

The front panel is a mesh design, which is the right call for a case marketed on airflow. The mesh is reasonably fine, which means it catches dust effectively but doesn't choke intake airflow the way some overly restrictive mesh designs do. The side panel is a full-length tempered glass panel on the left side, giving you a clear view of the interior. The right side panel is solid steel, which is standard. There's no windowed right panel here, but honestly that's fine. Nobody's displaying their cable management on the back side.

The overall aesthetic is angular and aggressive in the way MSI's MPG line tends to be. There's an RGB strip visible through the front mesh that ties into the included fans. If you're running MSI's Mystic Light ecosystem, it integrates cleanly. If you're not, you can still control it via the front panel button or just turn it off. The case doesn't look out of place next to a monitor, and the black finish (the version I tested) is consistent and well-applied. No obvious paint drips or uneven coverage anywhere on the exterior.

One thing worth noting: E-ATX boards vary in their exact dimensions more than ATX boards do. Some high-end HEDT boards push the boundaries of what "E-ATX" means. MSI's own spec page lists the maximum supported board dimensions, and I'd recommend cross-referencing your specific board against those numbers before ordering. For the vast majority of builds, including dual-GPU workstation boards and high-end gaming boards, you'll be fine. But if you're running something unusual, check first.

The standoff positions are clearly marked on the tray, which sounds like a minor thing but genuinely saves time during a build. I've worked in cases where the standoff positions are ambiguous and you're squinting at the tray trying to figure out which holes are pre-tapped. The GUNGNIR 300P labels them clearly. The I/O cutout is large enough to accommodate most backplate designs without any clearance issues, and the area around the CPU socket has good access for installing and removing coolers after the board is mounted.

The vertical GPU mount is where the GUNGNIR 300P distinguishes itself. The PCIe 4.0 riser cable is included in the box, and the vertical mount bracket is integrated into the chassis rather than being a flimsy afterthought. Vertical clearance drops to around 340mm, which still fits most cards. The GPU stand is also included, which prevents GPU sag when mounted vertically. That's a proper, complete vertical mounting solution without needing to buy anything extra. I tested the vertical mount with the RTX 4080 Super and it held the card securely with no flex.

The distance between the vertical GPU mount position and the tempered glass side panel is approximately 40mm, which is enough to display the GPU properly without it being pressed against the glass. Some cheaper vertical mount implementations put the card so close to the glass that you can't see the GPU cooler properly, and the airflow situation becomes questionable. The GUNGNIR 300P's 40mm gap is adequate. It's not the 50mm you'd ideally want for maximum airflow to the GPU cooler, but it's workable. Worth keeping in mind if you're running a particularly hot triple-fan GPU in a warm room.

AIO radiator support is strong. The front supports up to 420mm, which in practice means a 360mm radiator with fan offset, or a 280mm radiator with room to spare. The top supports up to 360mm, though with a 360mm radiator on top you'll want to check RAM clearance. Tall RAM heatspreaders can conflict with top-mounted radiators in some cases. In the GUNGNIR 300P, the top radiator position sits far enough forward that standard-height RAM (up to about 40mm) clears without issue. If you're running 50mm+ heatspreader RAM, measure carefully.

The rear position takes a single 120mm fan or a 120mm radiator. I ran the system with the 360mm AIO at the front and the included rear 120mm fan as exhaust. Pump mounting for the AIO was straightforward, with the pump head sitting cleanly above the CPU socket area. Tube routing from a front-mounted 360mm radiator to a CPU socket in the upper-left of an ATX board is always a bit of a stretch, but the GUNGNIR 300P's internal dimensions give you enough slack to route the tubes without kinking. I've built in cases where that routing is genuinely stressful. This wasn't one of them.

The 2.5-inch bays are split between two positions on the back of the motherboard tray and two on the PSU shroud. The tray-mounted positions are tool-free with push-and-click sleds. The shroud-mounted positions use screws. It's a minor inconsistency, but not a problem in practice. M.2 drives mount directly to the motherboard, obviously, so the 2.5-inch bays are mainly for SATA SSDs or secondary storage. For a gaming build in 2026, two 3.5-inch bays and four 2.5-inch bays is more than enough. If you're building a NAS or a workstation with heavy storage requirements, you'd want a different case anyway.

One thing I noticed: accessing the 3.5-inch bays after the system is fully built requires removing the PSU shroud cover, which is two screws. It's not difficult, but it's not tool-free either. If you're regularly swapping drives, that's mildly inconvenient. For most people who set their storage up once and leave it, it's a non-issue. The drive cages themselves are removable if you want to free up space for longer PSUs or additional cable routing room, which is a useful option for very large PSU units.

The cable routing channels are cut into the motherboard tray at sensible positions: a large cutout behind the CPU area for the EPS cable, a cutout near the bottom-right for the 24-pin, and additional cutouts for GPU power and front panel connectors. The cutouts have rubber grommets, which keeps the finished build looking clean from the glass side. The PSU shroud has a large opening at the rear for routing PSU cables up through the shroud, and the shroud itself is solid enough that it doesn't flex when you're pushing cables through.

I ran a fully modular 850W PSU in this build with a complete set of sleeved cables, which is about as demanding a cable management scenario as you'll encounter in a mid-tower. Everything routed cleanly. The 24-pin cable had enough slack to route behind the tray and come back up through the cutout without straining. The EPS cable (which is always the awkward one on boards with the connector at the top-left) had just enough length to reach with a standard 650mm EPS cable. If you're using a shorter cable or a board with an unusual EPS position, check your cable lengths before building.

I ran thermal logging over two weeks with the Ryzen 7 7800X3D and RTX 4080 Super configuration. Under sustained gaming load (one hour of Cyberpunk 2077 at 4K), CPU temperatures stabilised at 72 degrees Celsius with the 360mm AIO at the front. GPU temperatures peaked at 78 degrees Celsius with the card mounted horizontally. Switching to vertical GPU mounting added approximately 3-4 degrees to the GPU temperature, which is consistent with the reduced airflow from the 40mm glass clearance. That's an acceptable trade-off for the aesthetics, but worth knowing if you're running a card that already runs warm.

The included 120mm fans are decent for bundled fans. They're not the quietest fans I've heard, but at medium speed they're inaudible over normal ambient noise. At full speed they produce a noticeable whoosh, but the system's fan curve rarely pushed them that hard under gaming loads. The MSI product page lists the fans as supporting PWM control, and they responded correctly to the motherboard's fan headers during testing. If you want to replace them with higher-performance fans later, the front panel accommodates 120mm or 140mm fans (with some bracket adjustment), giving you upgrade flexibility.

The power button is a large circular button with an RGB ring around it, which looks good and has a satisfying click. The reset button is smaller and sits next to it. The button placement is sensible, with the power button clearly differentiated from the reset button by size and position. I've used cases where the reset button is dangerously close to the power button and you end up accidentally resetting the system when you meant to turn it on. Not a problem here. There's also a dedicated button for cycling through RGB lighting modes, which is a nice touch if you're not using software control.

The audio jack quality is fine for a case-level implementation. I tested it with a pair of open-back headphones and a condenser microphone, and the signal was clean with no audible interference from the system components. That's not always guaranteed with front panel audio, particularly in cases where the audio header cable runs close to GPU power cables. The GUNGNIR 300P routes the audio cable away from the main power cable bundle, which helps. If you're doing serious audio work, you'd be using a dedicated audio interface anyway, but for gaming headsets and casual use, the front audio is perfectly adequate.

The 4mm tempered glass side panel attaches with four thumbscrews and hinges open from the front. The hinge mechanism is smooth and the panel sits flush when closed. The magnetic dust filter on the front panel is a proper magnet, not a weak one that falls off when you tilt the case. The top dust filter slides out from the back, which is the correct design because it means you can clean it without moving the case. The PSU dust filter at the bottom is removable from the rear. All three filters are fine mesh, not coarse mesh, which means they actually catch fine dust particles rather than just large debris.

Panel alignment across the chassis is good. The front panel sits flush with the top and bottom panels with no visible gaps. The tempered glass panel aligns correctly with the chassis frame. The only minor quality note I'd make is that the front mesh panel has a slight amount of flex if you press on it firmly, which is inherent to mesh panel designs rather than a specific fault with this case. It's not a structural issue, just something to be aware of if you're the type who leans on their case. The overall build quality is consistent with the price point and better than some competitors at the same level.

The Corsair 4000D Airflow is a slightly smaller case with no E-ATX support and no included vertical GPU mount. It's a cleaner, simpler build experience with excellent airflow, but it doesn't bring the vertical mounting hardware or the PCIe 4.0 riser cable to the table. The Fractal Design Meshify 2 supports E-ATX and has a strong reputation for build quality, but it doesn't include a riser cable and its vertical GPU support requires an optional add-on bracket. The GUNGNIR 300P's value proposition is that the vertical mounting ecosystem is complete out of the box, which is a genuine differentiator at this price point.

Where the GUNGNIR 300P loses ground is in the overall build experience polish. The Fractal Meshify 2 has slightly better cable management routing in my experience, with wider channels and more Velcro strap points. The Corsair 4000D is a more refined build experience for straightforward ATX builds. But neither of those cases includes a PCIe 4.0 riser cable, and buying one separately narrows the price gap considerably. If vertical GPU mounting is part of your build plan, the GUNGNIR 300P's all-in pricing makes a strong argument.

The thermal numbers from two weeks of testing back up the airflow claims. CPU and GPU temperatures under sustained load were competitive with other mesh-front cases in this bracket. The 4mm tempered glass, the rolled steel edges, and the magnetic dust filter are all details that suggest MSI paid attention to what builders actually care about. The front I/O with 20Gbps USB Type-C is ahead of most competitors at this price, and the E-ATX support gives you room to grow into a larger platform if your build plans change.

The things that hold it back from a perfect score are relatively minor. The cable management, while good, doesn't quite match the Fractal Meshify 2's routing options. The vertical GPU clearance to the glass is 40mm rather than the 50mm that would be ideal for maximum GPU airflow. And the front mesh panel has a slight flex to it that more premium cases avoid. None of these are deal-breakers. They're just the honest trade-offs you make at this price point. Overall, this is a strong case for the money, particularly for builders who have vertical GPU mounting on their wishlist. I'd score it 8.5 out of 10.