Gamemax RGB PRO 750G power supply review: Efficient, but pricey for an average unit with pretty lights

Gamemax is a brand behind an OEM (Sohoo), founded to retail its own products. Founded in 2013, the company sells cases, coolers, monitors, peripherals, and power supplies under a positioning it calls affordable luxury, which in practice means visually loud products at prices that undercut the established names. Its power supply catalog has always been the most uneven part of the range. There are units at the bottom of the stack that exist purely to hit a price, and there are recent models such as the Lion Core series that carry genuine certification and measure respectably. Knowing which of the two a given Gamemax supply belongs to has historically required someone to open it up and put it on a load tester, because the badge on the box does not settle the question.

We examine the Gamemax RGB PRO 750G to see how it fares among the best power supplies on the market. The RGB PRO series sits in the middle of that catalog and leads with its lighting. The 750G reviewed here is the 750W model, a fully modular ATX unit built around a 140 mm ARGB fan, compliant with ATX 3.1 and PCIe 5.1, and fitted with a native 12V-2x6 connector for current graphics cards. Gamemax rates it at 40°C ambient and lists an operating range up to 50°C, with the important caveat that output is derated by twenty percent above 40°C, so anyone running it in a genuinely hot environment is buying a 600W supply.

The company claims 80 PLUS Gold efficiency, Japanese 105°C main capacitors, and 25 addressable lighting modes with motherboard sync. The Gold claim is the one worth pausing on, because no entry for this model exists in the CLEAResult 80 PLUS database, nor in the Cybenetics or PPLP databases, so the badge printed on the sticker is at present a manufacturer assertion and nothing more. At an MSRP of $105, the RGB PRO 750G is asking more than several other 750W Gold units currently sell for, which places a great deal of weight on the lighting to justify the difference.

Specifications and Design

In the Box

The RGB PRO 750G arrives in a black cardboard box with a render of the unit on the front, the model name and wattage set large across the top, and three badges in the top right corner: PCIe 5.1 ready, ATX 3.1 ready, and a warranty shield. Green pinstripes run vertically across the artwork, the word Gamemax is spelled out letter by letter along the bottom edge, and an RGB color wheel with the words RGB LIGHT VERSION occupies the corner. It is busy but legible, and the front of the box tells a buyer most of what they need to know.

Protection inside is adequate rather than generous, with the supply held between two molded pieces and the cables bagged separately. The bundle is thin. There is the AC power cord, four mounting screws, two zip ties, a multilingual user manual, and a 5V three-pin ARGB cable for motherboard synchronization. The ARGB cable is the one item a competitor would not usually include, and given the feature set, it is a necessity rather than a bonus.

All of the unit’s cables are individually sleeved in black braid. Gamemax's marketing describes the whole set as “embossed flat cables”. Wire gauges look appropriate throughout. These sleeved cables are slightly stiffer than flat ones and take more effort to route behind a motherboard tray, which is the usual trade for looks and ruggedness.

External Appearance

At 165 x 150 x 86 mm, the RGB PRO 750G is a slightly long power supply. The 165 mm depth is 25 mm more than the ATX design guide recommendation, which is commonly met by 750W units. While every full-size ATX case will likely take it, cable clearance behind the unit in a mid-tower with a shroud will be tighter than it should be. The chassis is all black with a slightly textured matte finish that, for some reason, is very sensitive to fingerprint marks. It is a decent paint job, evenly applied. Four exposed screws hold the fan in place.

The top face is dominated by a hexagonal honeycomb grille stamped directly into the panel rather than a separate wire guard, with a Gamemax lion badge at the hub of the fan. The specification sticker occupies the opposite face, printed clearly, and includes the full rail table, the safety marks, and an 80 PLUS Gold logo. The side panels carry a large 750W in outline type with RGB LIGHT VERSION beneath it and the lion logo rendered in a rainbow gradient, alongside a further honeycomb perforated section.

The rear face holds the C14 receptacle, a recessed main rocker switch, and a small square button labelled RGB LIGHT, all set into a perforated exhaust panel that covers most of the available area. The front face is the fully modular connector bay, arranged in two rows and silkscreened above and below each socket. A three pin 5V ARGB header sits at the left edge of the bay for the sync cable.

The lighting is the reason this model exists, and it is better executed than the price suggests. A ring of addressable LEDs sits under the perimeter of the fan opening and lights the honeycomb cells from beneath, so the effect is a glowing hexagonal halo rather than the illuminated fan blades most RGB supplies use. It is diffused, even, and free of the visible hot spots that give away cheap LED strips, and it looks considerably more expensive than it is. Gamemax claims 25 modes, cycled with the rear RGB LIGHT button.

A short press steps to the next mode, holding the button for three seconds switches the lighting off, pressing again restores the previous mode after a single white flash, and a longer hold enters a self-test that lights every LED white. The last mode is retained through a power cycle. Connecting the bundled cable to a 5V three-pin header on the motherboard hands control to the board's own software instead. However, the lighting is on the fan face, and in any case, with a bottom-mounted shroud, the conventional fan-down orientation buries the whole effect. Seeing it requires mounting the unit fan up, which most cases allow but which compromises intake air for the supply itself.

Internal Design

Cooling comes from a 140 mm fan is made by PowerYear, model PY-14025H12S, rated at 12V and 0.40A. We could not find a datasheet for it. Gamemax claims a fluid dynamic bearing (FDB) engine fan and has a 50,000-hour life expectancy. The “S” designation suggests a sleeve bearing, but fan OEMs are infamous for mixing SKUs, so we cannot say be certain of the engine inside it. In a unit with a 10-year warranty, we would certainly hope that Gamemax’s claims are accurate.

The platform is a Sohoo design. Guangdong Sohoo Technology is behind Gamemax, which is a Chinese manufacturer better known for cases and entry-level supplies than for anything with grand ambitions, but they have begun looking up lately. The layout is tidy for the class. Component placement is orderly, the soldering on the underside is clean, and the heatsinks are properly sized rather than the token strips of aluminum that usually accompany a budget platform. The extra 25 mm of chassis depth is put to use, as the board is not crowded and airflow is virtually unrestricted. None of this is bad work.

The transient filtering stage begins on a small vertical PCB mounted behind the AC receptacle and continues on the main board, comprising two Y capacitors, two X capacitors, two common-mode chokes, and a MOV. That is a basic but complete filter with nothing omitted. Inrush current is handled by an NTC thermistor with a relay for bypass duty. A single bridge rectifier is mounted on the main heatsink alongside the APFC components. The active PFC stage uses two Oriental Semiconductor OSG55R140F MOSFETs and stores energy in a Nichicon 390 μF, 420V capacitor rated to 105°C, from the CE GG series. That capacitor is the one Gamemax's marketing points to when it advertises Japanese capacitors, and on the primary side, the claim is accurate. The boost coil is unshielded.

The primary inversion stage is built from two Si-Trend SI23N50F MOSFETs in a half-bridge arrangement, also sharing the long heatsink with the APFC components and feeding the main transformer. The resonant components alongside it indicate an LLC resonant converter, the standard and sensible choice for a Gold-class unit of this size.

On the secondary side, the 12V rail is produced by four SPTJ4R1D6LA MOSFETs in synchronous rectification, a part we could not attribute to a known vendor. The 3.3V and 5V rails are generated by DC-to-DC converters on a vertical daughterboard adjacent to the modular PCB. Secondary filtering is where the cost comes out. Every secondary capacitor in this unit is supplied by Teapo. Teapo parts are not bad, and the ones fitted here are 105°C rated, but they are the middle-budget choice, which explains why the marketing claim about Japanese “main capacitors” looks carefully worded. With 10 years of warranty behind them, the secondary capacitors are the wrong place to have economized.

Cold Test Results (25°C Ambient)

Cold Test Results (25°C Ambient)

For the testing of PSUs, we are using high-precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high-precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox, and various other bits and parts.

At 25°C ambient, the RGB PRO 750G measures considerably better than its provenance would suggest. Efficiency averaged 90.8% across the nominal load range at 230 VAC and 88.6% at 115 VAC, peaking at 92.1% near 40% load on the higher input and 90.3% at roughly the same point on the lower one. Full load returns 90.7% and 87.2%, respectively, and the curve falls away gently rather than collapsing. Those are real Gold numbers. At 115 VAC the unit returns 88.3% at 20% load, 90.0% at 50% and 87.2% at 100%, which clears the 80 PLUS Gold thresholds of 87%, 90% and 87%, though two of the three points clear them by a thin margin. The performance is there. What is not there is any independent confirmation of it, since no entry for this model appears in the CLEAResult, Cybenetics, or PPLP databases, and an 80 PLUS Gold logo on a sticker with nothing behind it is a claim, not a real certification.

Thermally, the unit is excellent, and acoustically it pays for that. The primary heatsink reached 51.0°C and the secondary 47.8°C at full load, with exhaust air leaving at 39.7°C against a 25.2°C intake, a delta of 14.5°C. Those are figures we would expect from a considerably more expensive supply, and they are achieved the obvious way. There is no semi-passive mode, and the cooling profile is a little aggressive. The fan turns on from the moment the unit is powered, and it stays close to the base through the first 300W, drifting only to 33 dB(A). Past 400W, the curve turns sharply upward, reaching 43.0 dB(A) at 525W, 45.2 dB(A) at 600W, and close to 50 dB(A) at a sustained 750W. Below 300W, this is a quiet supply, and the absence of a fanless window costs it very little, as it is practically inaudible. Above 500W, it is one of the louder 750W units we have measured, and in a quiet build it will be the component you hear.

Hot Test Results (~45°C Ambient)

Hot Test Results (~45°C Ambient)

Inside the hotbox at approximately 45°C ambient, into the range where Gamemax derates it, efficiency moves, but not dramatically so. The average fell to 89.8% at 230 VAC and 87.7% at 115 VAC, with full load figures of 89.3% and 85.9%. A single point of degradation at 230 VAC across a 20-degree ambient rise is a genuinely good result for the class of this unit. The 115 VAC curve suffers more than the 230 VAC one, falling below 86% at maximum output, which is where the manufacturer's derating starts to look like sound engineering rather than marketing caution, as the signs of thermal stress become obvious.

Internal temperatures stayed under control. The primary heatsink reached 80.8°C and the secondary 76.3°C at full load, well within the ratings of the components fitted, and the exhaust delta is essentially unchanged from the cold run. Once again, the fan is doing the work. It starts at 37.7 dB(A) even at 37.5W, passes 45 dB(A) before 300W, reaches 50 dB(A) at half load, and finishes at 54.4 dB(A) at a sustained 750W. That is loud in the plain sense of the word, and it makes sustained heavy load in a warm case an unpleasant proposition. It is a unit that will stay cool and reliable, but acoustics are being sacrificed for it.

PSU Quality and Bottom Line

Power Supply Quality

Voltage regulation is good rather than exceptional. Across the 20% to 100% load span, the 3.3V rail moved by 1.1%, the 12V rail by 1.4%, and the 5V rail by 1.5%. The 12V line ran from 12.12V at 20% load down to 11.95V at maximum output, which is 0.4% below nominal and entirely comfortable. The 5V rail sags to 4.97V at full load and the 3.3V rail to 3.31V. Neither minor rail is generously specified in the first place, at 15A each and 80W combined, but modern systems ask almost nothing of them and the figures are of academic interest for most builders. Ripple suppression is the strongest single result in this review. The 12V rail peaked at 48 mV under full load against the 120 mV ATX design limit, leaving 60% headroom on the rail that matters. The 5V rail topped out at 28 mV and the 3.3V rail at 26 mV against their 50 mV limits, with roughly 44% and 48% headroom respectively. However, all three rails stayed almost perfectly flat across the load range rather than degrading as output climbed, which behavior is rather odd for a PC PSU, as they tend to perform better when lightly loaded.

During our thorough assessment, we evaluate the essential protection features of every power supply unit we review, including Over Current Protection (OCP), Over Voltage Protection (OVP), Over Power Protection (OPP), and Short Circuit Protection (SCP).

All protection mechanisms triggered correctly with the unit hot. OCP tripped at 136% on the 3.3V rail, or 20.4A, and at 132% on the 5V rail, or 19.8A. The 12V rail is the outlier. OCP intervened at 108%, equivalent to 67A against a 62A rating, which is a far tighter margin than we normally see and tighter than we are comfortable with on an ATX 3.1 supply. Modern graphics cards produce short excursions well above their rated draw, and a 12V protection point set 8% above the rail rating leaves very little room for them. OPP shut the unit down at approximately 110% of rated output, or 825W, which is similarly conservative. Nothing here is unsafe. The unit is simply less tolerant of transient behavior than its ATX 3.1 badge implies, and a system pairing an ATX 3.1 class graphics card with a supply already running near its rated output is the scenario we would be cautious about.

Bottom Line

The RGB PRO 750G is two products fighting each other. Underneath there is a Sohoo platform that is competently engineered, properly filtered, generously heatsinked for the class, and that holds its efficiency in heat better than many mainstream Gold units. The Nichicon primary capacitor is a real one, and the ripple figures, although not record-breaking, are the best part of the review. On top of it sits a lighting ring, a set of marketing claims that do not survive checking, and a price that assumes you want the first of those enough to stop asking questions about the second.

The measurements support the 80 PLUS badge even though there is no published certification for this particular model. An average of 90.8% at 230 VAC and 88.6% at 115 VAC are honest Gold numbers, and the 115 VAC curve clears the 80 PLUS Gold thresholds at all three checkpoints, if narrowly at two of them. Regulation is comfortable on every rail, and ripple has more than half its allowance spare on the 12V line. Internal temperatures are excellent in both ambients. Nothing in the electrical results embarrasses the unit.

The compromises are concentrated in three places. The secondary capacitors are all Teapo, which is the middle-budget choice and sits awkwardly against marketing that advertises Japanese capacitors without mentioning that only one of them is. The fan is a PowerYear part whose engine we cannot confirm, and it never stops; while that buys the excellent thermals, it also produces noise, which places this among the louder 750W supplies at high load. And the 12V OCP point of 67A, only eight percent above the rail rating, is tighter than a supply carrying an ATX 3.1 badge should be, given what current graphics cards do to a 12V rail on a millisecond scale. The warranty is the part of the package doing the most work. Ten years is serious coverage, level with MSI and three years beyond Corsair, and on a unit whose secondary capacitors are the obvious economy, it is the reassurance that makes them tolerable. It is also the clearest signal that Gamemax expects this platform to last, which the thermal results support.

The pricing is where the argument gets difficult. At $105, the RGB PRO 750G is not the cheap option, which is the position a Gamemax supply usually occupies and the one this feature sheet is built for. The MSI MAG A750GL PCIE5 and the Corsair RM750e both sell below it routinely, frequently closer to eighty dollars, and both carry certification that exists in a public database along with quieter behavior at high load. Against that pair, the Gamemax is behind on certification, behind on acoustics, level with MSI and ahead of Corsair on warranty, competitive on efficiency, ahead on ripple, and 25 mm longer in the chassis. Against the Cooler Master MWE Gold 750 V4 at $119, it saves fourteen dollars and matches the coverage, giving up the conformal coating and the better-documented parts sheet to do it. It wins outright on exactly one axis, and that axis is decorative.

The engineering does not deserve dismissal, and anyone who assumes an RGB badge guarantees a bad power supply will be wrong about this one. It measures well, it runs cool, it is covered for a decade, and none of that is an accident. But competence is the floor in this segment rather than the selling point, and $105 asks a buyer to pay above the going rate for a unit that leads on decoration and merely keeps pace on everything else. If the ARGB halo is what you want, and your case mounts the supply fan up where you will actually see it, this is a defensible purchase that will not let you down. If it is not, the same money buys a certified, quieter, equally well-covered supply from a brand with a longer record, and that is the comparison Gamemax still has to answer.

MORE: Best Power Supplies

MORE: How We Test Power Supplies

MORE: All Power Supply Content