Start Here: Why the Lian Li B4-mATX Is the Smart Default
A mini ITX case or compact mATX chassis is a small form factor PC enclosure designed to fit space-saving motherboards while still supporting modern graphics cards, effective cooling, and clean cable management for high-performance systems in tight spaces. For most builders, the Lian Li B4-mATX is the right place to start. It is a compact PC case measuring 420 × 191 × 288 mm that accepts only Mini-ITX and M-ATX motherboards. That focus on smaller boards lets it deliver serious hardware density without feeling cramped. At USD 69.99 (approx. ₱3,900), it undercuts many premium small form factor options while still giving you dual pre-installed 120 mm top fans and room for extra fans on the front, bottom, and sides. If you want a powerful mATX motherboard build in a footprint that still fits on a crowded desk, this is the case to buy.
Lian Li B4-mATX: Compact Muscle for High-End GPUs
The Lian Li B4-mATX proves that a compact PC case does not mean low performance. At 420 × 191 × 288 mm, it is small enough that only Mini-ITX and M-ATX motherboards fit, yet it can house even some of the largest RTX 5080 graphics cards. It ships with two 120 mm fans on the top, plus mounts for one more in the front and three more on both the bottom and sides. That much fan capacity in a small volume is exactly what you want for a high-wattage small form factor PC. If you plan on a 360 mm AIO, you must pair it with an SFX power supply due to space limits—a clear example of how thermal management in tight spaces requires careful cooler and PSU selection. According to one review, “that doesn’t mean you can’t pack an oversized GPU in the B4-mATX though, even some of the largest RTX 5080 models can be installed”.
CPS C3 M500: Affordable Panoramic Case for Bigger Builds
If you want more room and a showpiece build without spending much, the CPS C3 M500 is the panoramic mid-tower to buy. Priced at an estimated USD 48–49 (approx. ₱2,700–₱2,800), it targets budget-conscious enthusiasts while offering a triple tempered glass front, top, and left panel for a wide view of your hardware. It supports ATX, Micro-ATX, and Mini-ITX motherboards, GPUs up to 400 mm long, CPU air coolers up to 157 mm tall, and ATX PSUs up to 200 mm long. That 157 mm air cooler clearance is helpful when checking ITX cooler compatibility in compact builds that still rely on tower coolers. With mounting for up to seven 120 mm fans and a 360 mm radiator on the side, it pairs well with high-core-count CPUs and powerful GPUs. Storage is solid, with two 3.5-inch bays and three 2.5-inch SSD mounts, plus seven PCIe slots for expansion.
| Spec | Lian Li B4-mATX | CPS C3 M500 |
|---|---|---|
| Price | USD 69.99 (approx. ₱3,900) | USD 48–49 (approx. ₱2,700–₱2,800) |
| Supported motherboards | Mini-ITX, mATX only | ATX, Micro-ATX, Mini-ITX |
| Dimensions (W × D × H) | 191 × 288 × 420 mm | 277 × 418 × 440 mm |
| Fan support | 2 × 120 mm included top; +1 front, +3 bottom, +3 side mounts | Up to 7 × 120 mm (3 side, 3 bottom, 1 rear) |
| Radiator support | 360 mm AIO possible with SFX PSU | Up to 360 mm side radiator |
| Max GPU length | Supports even some of the largest RTX 5080 cards | Up to 400 mm |
| Max CPU cooler height | Not specified | 157 mm |
| PSU type/size | Requires SFX PSU for 360 mm AIO | ATX PSUs up to 200 mm |
Cooling, Compatibility, and Cable Management in Tight Spaces
Once you choose a compact PC case, thermal planning comes next. In the B4-mATX, a 360 mm AIO is possible only if you use an SFX PSU, so your cooling and power choices are tightly linked. The C3 M500 makes radiator placement simpler with direct support for a 360 mm side-mounted radiator, while seven 120 mm fan positions let you tailor airflow to hot spots. ITX cooler compatibility in the C3 M500 is straightforward: any air cooler up to 157 mm tall will fit. Component compatibility and cable management become critical in space-limited builds; pillarless glass in the C3 M500 helps builders display clean cable runs and liquid cooling hardware. Budget-conscious options like the C3 M500 deliver a panoramic view of modern high-end GPUs and radiators without premium pricing. In short, plan your motherboard, PSU, and cooling as a single system, not separate parts.
Buy if / Skip if
- Buy the Lian Li B4-mATX if you want a compact mATX motherboard build that can still handle oversized GPUs and strong airflow.
- Skip the Lian Li B4-mATX if you refuse to use an SFX PSU but still want a 360 mm AIO in a tight small form factor PC.
- Buy the CPS C3 M500 if you want an affordable panoramic case with triple tempered glass and support for ATX, Micro-ATX, and Mini-ITX boards.
- Skip the CPS C3 M500 if you need a truly space-saving mini ITX case rather than a wider mid-tower footprint.
- Buy the CPS C3 M500 if you care about ITX cooler compatibility and need up to 157 mm air cooler clearance with a 360 mm radiator option.
- Skip the Lian Li B4-mATX if you prefer a wide-open interior for easy cable management instead of the tighter routing of a compact PC case.
