The mini ITX shortlist

The best mini ITX case in the UK is the Cooler Master NR200P V3 at £169.89 on Amazon UK at the time of writing (October 2026). It fits a 361.5 mm graphics card up to 3.8 slots thick, a 280 mm AIO on the roof and an SFX power supply in 18.62 litres, and Cooler Master includes a PCIe 5.0 riser cable. The Fractal Design Terra at £174.98 is the best-looking small form factor case, and the Lian Li A4-H2O at £142.92 is the smallest here that takes a 240 mm AIO, at 11 litres.

Every mini ITX case trades parts for size. All five picks take SFX power supplies, four mount the graphics card on a riser cable, and only the Cooler Master NR200 fits a tower cooler. These picks sit under Best PC case UK 2026; the size classes are compared in PC case sizes explained, and the next size up is in Best micro ATX case UK 2026.

What is the best mini ITX case?

The Cooler Master NR200P V3 is the best mini ITX case for a high-end gaming PC because it has the most graphics card room and the biggest radiator mount of the five. Cooler Master lists 361.5 mm of graphics card length including the power connector, 26.5 mm more than the Fractal Design Ridge at 335 mm, and a roof mount for 240 mm or 280 mm radiators.

The catch is the CPU cooler. The V3 mounts the graphics card vertically beside the motherboard on its riser, which caps air coolers at 70 mm, so the NR200P V3 is an AIO case. Buyers who want a tower air cooler should pick the original Cooler Master NR200, which fits a 155 mm cooler for £67.25 less.

1. Cooler Master NR200P V3 - best mini ITX case

The Cooler Master NR200P V3 costs £169.89 on Amazon UK at the time of writing (October 2026). It keeps the NR200 family's 18-litre footprint but moves to a vertical layout: the graphics card stands on a bundled PCIe 5.0 x16 riser behind a removable mesh side panel, and a 240 mm or 280 mm AIO cools the CPU from the roof. Nvidia lists the RTX 5090 Founders Edition at 304 mm long and two slots thick, so it fits with 57.5 mm of length to spare.

Panels are aluminium, steel and mesh, with a USB-C 20Gbps port on the front. There are no fans in the box and only three fan mounts: two on the roof, which the AIO's fans fill, and one underneath. The 70 mm air cooler limit rules out tower coolers, and Cooler Master caps the power supply at SFX or SFX-L.

2. Fractal Design Terra - best-looking mini ITX case

The Fractal Design Terra costs £174.98 on Amazon UK at the time of writing (October 2026) in Silver, the dearest pick and the smallest at 10.4 litres. Fractal pairs anodised aluminium side panels with an 8 mm-thick aluminium front and solid FSC-certified walnut, and the top and side panels lock for carrying. It weighs 3.1 kg, and the Amazon UK listing includes a PCIe 4.0 riser cable.

The Terra's central wall slides through 30 mm to share space between the graphics card and the CPU cooler. Fractal lists a 72 mm graphics card, about 3.5 slots, alongside a 48 mm CPU cooler; moving the wall gives the cooler more room and the card less. A 47 mm Thermalright AXP90-X47 at £24.59 or Noctua's 37 mm NH-L9a-AM5 at £39.95 fits at the full card setting. Fractal lists one 120 mm fan mount and a 120 mm side radiator, so cooling is the price of the looks.

3. Lian Li A4-H2O - smallest with AIO support

The Lian Li A4-H2O costs £142.92 on Amazon UK at the time of writing (October 2026) in black. It is a DAN Cases design built by Lian Li, based on the DAN A4-SFX, with an aluminium exterior and a separate top section for a 240 mm AIO. At 11 litres it is 0.6 litres larger than the Fractal Design Terra, but it cools the CPU with a 240 mm radiator where the Terra takes a 120 mm one.

The graphics card sits in a sandwich layout on the included PCIe 5.0 riser and can be triple-slot and up to 322 mm long. Air coolers are limited to 55 mm, and the SFX or SFX-L power supply sits beside the motherboard. The NR200P V3 adds 7.62 litres for a 280 mm radiator and 39.5 mm more graphics card length.

4. Fractal Design Ridge - best for a living room PC

The Fractal Design Ridge costs £131.18 on Amazon UK at the time of writing (October 2026) and is built to sit under a TV like a games console. It is 110 mm wide, stands upright or lies flat, and comes with two Aspect 14 PWM fans and a PCIe 4.0 riser, one of two picks with fans in the box. The front has a USB-C 20Gbps port and two USB-A ports for a controller and a wireless receiver.

Graphics card room is long but thin: Fractal lists 335 mm of length but only 57 mm of thickness, about 2.8 slots, so check a card's thickness before its length. CPU coolers are limited to 70 mm, and the only radiator position is a 120 mm on the side. The Ridge suits a living room PC with a two-slot card; the console alternative is weighed in Steam Machine vs PS5 Pro UK.

5. Cooler Master NR200 - best budget mini ITX case

The Cooler Master NR200 costs £102.64 on Amazon UK at the time of writing (October 2026) in black, £67.25 less than the NR200P V3, and it is the most forgiving mini ITX case here. The graphics card plugs straight into the motherboard, so no riser is needed, and the CPU gets 155 mm of cooler height, enough for a full tower air cooler. Cooler Master lists seven fan mounts, two pre-installed SickleFlow fans and side mounts for radiators up to 280 mm.

The trade-offs are the front panel, which has two USB-A ports and no USB-C, and a 330 mm, triple-slot graphics card limit. Cooler Master sells an ATX power supply bracket for the NR200 and NR200P at £12.99 on Amazon UK, so a spare ATX unit can be reused.

How big are mini ITX cases, and what are their limits?

The five picks run from 10.4 litres to 18.62 litres, against 26.3 litres for the smallest micro ATX pick, the Lian Li A3-mATX. Volume decides what fits, so Compare Electronic's size table puts every limit that matters on one row per case.

The NR200P V3 and NR200 are 75% to 79% larger than the Fractal Design Terra, and that volume buys a 280 mm radiator. The Lian Li A4-H2O is the exception that gets a 240 mm radiator into 11 litres.

What fits in a mini ITX case? A checklist

Check nine things against the case spec sheet before ordering parts: board, graphics card length and thickness, cooler type, radiator, power supply, riser and fans. Compare Electronic's checklist shows which of the five picks pass each one.

Graphics card thickness catches more builds than length. Partner cards are often thicker than Nvidia's two-slot Founders Edition, so check the millimetre figure on the card's spec page against the Ridge's 57 mm and the Terra's 72 mm. Card picks are in Best graphics card UK 2026.

Do mini ITX cases need an SFX power supply?

Yes: all five picks take SFX or SFX-L power supplies as standard. SFX units measure 125 x 63.5 x 100 mm and SFX-L units 125 x 63.5 x 130 mm under Intel's SFX12V design guide, against 150 x 86 x 140 mm for an ATX unit.

SFX costs a little more per watt. On Amazon UK at the time of writing (October 2026), the Lian Li SP750 V2 750 W SFX unit costs £107.99 and the Corsair SF750 (2024) Platinum £144.95, against £99.00 for Corsair's RM750e (2025) ATX unit. Nvidia lists 1,000 W of system power for the RTX 5090 Founders Edition, and SFX reaches that: the Lian Li SP Platinum 1000W SFX costs £159.95. Short cables matter in a 10 to 18 litre case; custom-length sets are covered in Best sleeved PSU cables UK 2026.

Do you need a PCIe riser cable, and does PCIe 4.0 vs 5.0 matter?

A riser is needed in any sandwich-layout or vertical-mount case, and four of the five picks include one: PCIe 5.0 in the NR200P V3 and A4-H2O, PCIe 4.0 in the Terra and Ridge. The Cooler Master NR200 mounts the card in the motherboard slot and needs none.

A PCIe 4.0 riser costs a 16-lane card little. TechPowerUp measured the RTX 5090 about 1% slower at PCIe 4.0 x16 than at PCIe 5.0 x16, and 4% slower at 1080p and 1440p at PCIe 3.0 x16. Eight-lane cards are the case to watch: the RTX 5060 family uses x8, so on a PCIe 4.0 riser it runs at PCIe 4.0 x8, the bandwidth of PCIe 3.0 x16. The RX 9060 XT uses all 16 lanes.

Builders pairing a PCIe 5.0 card with a PCIe 4.0 riser can lock the slot to Gen 4 in the BIOS to avoid link errors. Tom's Hardware checks a riser by setting the PCIe mode in the BIOS, running Furmark and confirming the link speed in GPU-Z.

Do small form factor PCs run hotter?

Yes, when the panels restrict airflow: Tom's Hardware measured the Cooler Master NR200P Max with a 280 mm AIO at a 70.5 °C CPU peak and a graphics card just under 60 °C with the mesh side panel, then a 3.5 °C rise for the CPU and a 13.5 °C rise for the graphics card with the glass panel fitted, under Prime95 and Furmark normalised to 20 °C.

Mesh panels and fan mounts matter more in 10 to 18 litres than in a mid tower. The NR200 holds seven fans and the NR200P V3 ships with a mesh side panel. The Terra has one 120 mm fan mount and a 48 mm cooler at full graphics card thickness, so it suits a 65 W CPU such as AMD's Ryzen 5 9600X better than the 120 W Ryzen 7 9800X3D. CPU picks are in Best CPU for gaming UK 2026.

How much more does a mini ITX build cost than micro ATX?

About £237 more for the case, motherboard and power supply, by Compare Electronic's sum of Amazon UK prices at the time of writing (October 2026). The motherboard is the biggest line: the cheapest B850 Mini-ITX board found, the ASUS ROG Strix B850-I Gaming WiFi, costs more than twice a B850 micro ATX board.

The SFX premium is small at 750 W, £8.99 between two Gold units, and rises to £45.95 for the Platinum Corsair SF750. Buyers who want a small PC without the board premium should start with Best micro ATX case UK 2026; the full parts budget is in Build vs buy a gaming PC UK 2026.

Verdict

The Cooler Master NR200P V3 at £169.89 is the best mini ITX case in the UK: a 361.5 mm, 3.8-slot graphics card, a 280 mm AIO and a PCIe 5.0 riser in 18.62 litres. The Fractal Design Terra at £174.98 is the best-looking and smallest, the Lian Li A4-H2O at £142.92 fits a 240 mm AIO into 11 litres, the Fractal Design Ridge at £131.18 belongs under a TV, and the Cooler Master NR200 at £102.64 is the budget pick and the only one for a tower cooler.

A mini ITX build costs about £237 more than micro ATX for the same graphics card. The full shortlist across every size is in Best PC case UK 2026.