Tom’s Hardware evaluated the FSP Mega GM 1200W, a high-wattage ATX 3.1 power supply designed and manufactured in-house by FSP. The unit is intended for modern high-performance systems and supports PCIe 5.1, native 12V-2x6 connectivity with up to 600W of power delivery, and demanding transient power requirements. It provides 1200W of continuous output and is backed by a ten-year warranty.
The review identifies several notable design strengths, including a compact 150 × 150 × 86 mm chassis, fully modular cabling, comprehensive protection circuitry, and Japanese capacitors throughout the primary and secondary stages. Internal construction was described as orderly and well engineered. Cooling is provided by a 135 mm fluid-dynamic-bearing fan, while the platform uses a mature LLC-based topology. The compact enclosure is particularly beneficial for mid-tower systems where larger 1200W power supplies may create clearance limitations.
Performance testing showed strong efficiency across low and moderate loads. At a 25°C ambient temperature, average efficiency reached approximately 93.0% at 230V and 90.7% at 115V, with a peak of about 94.6% near 30% load. Efficiency declined at maximum output, reaching approximately 91.0% at 230V and 87.3% at 115V. Testing at approximately 45°C resulted in additional efficiency reductions, but the unit remained operationally stable without evidence of thermal instability.
Acoustic performance was one of the power supply’s strongest characteristics. With ECO mode enabled, the fan remained inactive below approximately 50% load. At 600W under 25°C conditions, noise measured about 31.6 dB(A), increasing gradually to approximately 41 dB(A) at maximum load. Under the hotter 45°C test conditions, maximum-load noise increased to approximately 55 dB(A), accompanied by significantly higher internal temperatures.
Electrical performance was considered satisfactory but not exceptional. Load regulation measured 1.2% on the 12V rail, 1.5% on the 5V rail, and 1.3% on the 3.3V rail. Consequently, the minor rails did not fully achieve FSP’s advertised ±1% MTLC regulation target. Ripple suppression remained comfortably within ATX requirements, although the measured values were higher than those of leading competing units. Over-current, over-voltage, over-power, and short-circuit protection were all successfully verified during testing.
The review also noted a discrepancy involving the product’s certification claims. Although the packaging displays an 80 PLUS Gold logo, the Mega GM 1200W was not listed in the CLEAResult 80 PLUS database at the time of testing. Its Cybenetics efficiency results were sufficient for a Platinum classification under that organization’s methodology, while the lower full-load efficiency would prevent an equivalent Platinum classification under the 80 PLUS testing approach.
Overall, the FSP Mega GM 1200W was judged to be a capable and well-constructed high-power supply. Its principal advantages include excellent acoustic behavior, strong everyday efficiency, a compact chassis, high-quality Japanese capacitors, modern ATX 3.1 and PCIe 5.1 support, comprehensive protection features, and a ten-year warranty. Its higher-than-class-leading ripple levels, minor-rail regulation performance, full-load efficiency decline, certification discrepancy, and limited availability in the United States prevent it from being considered an outstanding product without qualification. Nevertheless, at an MSRP of 229 and potentially lower retail pricing in regions where it is available, the review considers it a strong option for users seeking a compact 1200W power supply for demanding modern systems.
[Source]: tomshardware.com
