Best Small ATX Power Supplies for Compact Builds
The following small-form-factor ATX power supplies are designed for compact and space-conscious PC builds. They cover Mini ITX, Flex ITX, TFX and SFX styles, offering modular or semi-modular options and features like active PFC and multiple protections. This guide helps compare form factors, connector sets, and cooling approaches to match small chassis needs.
| Product | Brand | Watts | Form Factor | Modular |
|---|---|---|---|---|
| Apevia ITX-AP300W | Apevia | 300W | Mini ITX / Flex ATX | Non-modular |
| Apevia ITX-PFC500W | Apevia | 500W | Mini ITX / Flex ATX | Modular |
| Apevia SFX-AP500W | Apevia | 500W | SFX | Modular |
| Apevia TFX-AP300W | Apevia | 300W | TFX | Non-modular |
| Apevia ITX-PFC400W | Apevia | 400W | Mini ITX / Flex ATX | Modular |
Below are five compact power supplies that balance size, efficiency and protection features. Each entry includes its form factor, modularity, and typical cooling approach to help match small builds like SFF desktops, POS kiosks, or compact home theater PCs.
Apevia ITX-AP300W Mini Power Supply
Apevia ITX-AP300W is a Mini ITX/Flex ATX power supply with a compact footprint suitable for small form factor builds. It offers 300W maximum power and a basic connector set: 20+4pin main power, 8pin 12V(P4+4), plus two SATA and two 4-pin Molex connectors. Cooling relies on a small 40mm fan with double ball bearings to moderate heat in tight spaces.
Apevia ITX-PFC500W Mini ITX Power Supply
Apevia ITX-PFC500W is a modular Mini ITX/Flex ATX power supply rated up to 500W. It features a full range active PFC (90-264V) and multiple modern connectors including 6+2 PCIe slots, along with 20+4pin main power and 8pin 12V. A 40mm fan handles cooling, and the unit includes protection features to guard against faults during operation in compact builds.
Apevia SFX-AP500W Power Supply
The Apevia SFX-AP500W is a compact SFX form factor unit designed for Micro ATX and small desktops. It provides 500W with modular cabling, 1 x 20+4pin, 1 x 8pin (P4+4), plus 2x PCIe 6+2 and multiple SATA/Molex connectors. Its SFX size supports tight cases while offering robust PCIe support for mid-range graphics and CPU configurations.
Apevia TFX-AP300W Standard Flex ATX
Apevia TFX-AP300W is a Flex ATX power supply in a TFX footprint, designed for compact desktops and slim builds. It offers 300W continuous output with a standard 115-230V AC input range. It provides essential rails: +3.3V, +5V, and +12V, along with the necessary connectors for a lightweight, space-efficient system. The unit emphasizes reliability within limited spaces.
Apevia ITX-PFC400W Modular Power Supply
Apevia ITX-PFC400W is a modular Mini ITX/Flex ATX power supply with full-range Active PFC (90-264V) and 400W maximum power. It features a modular main power and 8pin 12V P4+4, plus 6+2 PCIe, SATA, and Molex connectors. A 40mm cooling fan and multiple protection mechanisms address heat and safety in tight builds, making it suitable for compact gaming or small server setups.
Buying Guide: Key Considerations for Small ATX Power Supplies
When selecting a compact power supply, balance size, power needs, and future expansion. Consider these perspectives:
- Form factor compatibility: Mini ITX, Flex ATX, SFX and TFX vary in dimensions and mounting options. Confirm your case supports the chosen form factor.
- Wattage headroom: Small builds may still need 300–500W for mid-range GPUs and CPUs. Avoid under-sizing to reduce voltage drops and stability issues.
- Modularity: Modular or semi-modular units simplify cable management in tight spaces and improve airflow inside compact cases.
- Efficiency and noise: Look for 80 PLUS certification and a quiet cooling solution, especially if the system runs in a quiet environment or a small room.
- Protections: Ensure protections such as OVP, OCP, OTP and SCP are present to safeguard components in compact layouts with potential heat buildup.
- Reliability and MTBF: Higher MTBF values indicate longer expected lifespans, which is valuable in space-constrained, hard-to-service builds.
- Connector variety: Verify the required PCIe, SATA, and main power connectors match your motherboard and drives, particularly in modular systems.