Often, the requirements imposed on a product contradict each other or force the designers to find a middle ground: A high-wattage power supply achieving extremely high efficiency seems as unlikely as a sports car achieving 50 miles per gallon. However, the five PSUs in our test claim to do just that – one of them, the Corsair AX1500i, even specifies 90 to 94 percent efficiency at 1500 W sustained power. This power supply is the first power supply in our lab which is adorned by the 80 Plus Titanium logo – currently, there is no better rating. However, this impressive combination of power and efficiency comes at a hefty price: $450, almost twice what some Platinum-grade 1200 W PSUs command. Thus, if your use case doesn’t demand 1500 W or Titanium efficiency, you may be better advised to acquire a Platinum-grade 1200 W or 1300 W PSU. We included three of them in this test: The $280 Antec HCP-1300 Platinum, the $245 Cooler Master V1200, and the $270 Seasonic Platinum-1200. The fifth PSU in this test once again sports 1500 W, but at ‘merely’ Platinum efficiency: The Enermax Platimax EPM1500EGT, which doesn’t seem to be available in the U.S. yet.
But let’s return to the question: Who even needs such a powerful PSU? Average desktop PCs only need a 400 W PSU, if that. Some PCs even come with inexpensive 300 W PSUs. Even a high-end gaming rig typically doesn’t need more than a 750 W PSU, unless it contains multiple graphics cards. Using multiple graphics cards in a gaming PC is, however, a rare occurrence, as modern graphics cards are sufficiently powerful even for the most demanding games – there is simply no need for combining graphics cards via Nvidia’s SLI or AMD’s CrossFire. However, the demand for PSUs with more than 1000 W went through the roof during the past few months, and the reason is Bitcoin mining and Altcoin mining. Altcoin mining, by and large, still relies on graphics cards, although the first Scrypt ASICs are now available. However, Bitcoin mining rigs have not been based on graphics cards for more than a year – instead, these rigs are based on dedicated Bitcoin mining ASICs, whose DC-DC converters draw plenty of amps at 12 V. Enermax confirmed that the Platimax 1500 is flying off the shelves, and the same goes for all other high-wattage PSUs.
Lab Note: 80 Plus Certification at 230 V
Up till now, the 80 Plus organization Ecova Plug Load Solutions has been certifying PSUs at 115 V input voltage. 230 V-only PSUs were not eligible for the coveted 80 Plus certificate – conducting the test at 230 V would favor 230 V PSUs, as primary side currents, and by implication also resistive losses, are lower at 230 V. However, the certification agency recently introduced 80 Plus 230 V logos, whose efficiency thresholds are slightly more stringent, taking the higher efficiency of 230 V PSUs into account. That said, none of the PSUs in this round-up test, not even the 230 V-only Enermax Platimax, sported the new logo. Perhaps the 80 Plus 230 V logo is just too new.
Technical Specifications
| Products |
|
|
|
|
|
| Pricing |
|
|
|
Enermax
|
|
| Retail Price (Froogle.com) | $280 | $245 | $450 | n/a | $270 |
|---|---|---|---|---|---|
| Power Certification | 80 PLUS Platinum | 80 PLUS Platinum | 80 PLUS Titanium | 80 PLUS Platinum (not yet certified) | 80 PLUS Platinum |
| Dimensions (WxDxH) | 5.9” x 7.48” x 3.39” | 5.9”x 7.48”x 3.39” | 5.9” x 8.86” x 3.39” | 5.9”x 7.09” x 3.39” | 5.9”x 7.48”x 3.39” |
| Weight | 4.9 lbs. | 9.5 lbs. | 9.7 lbs. | 5 lbs. | 9.5 lbs. |
| Operating Temperature | 32 - 122 °F | 32 - 104 °F | 32 - 122 °F | 32 - 104 °F | 32 – 122 °F |
| Warranty | 7 years | 7 years | 7 years | 5 years | 7 years |
| Power Specifications | |||||
| Specification | ATX12V v2.4 | ATX12V v2.31 | ATX12V v2.4 | ATX12V v2.4 | ATX12V v2.4 |
| Specified Output Power | 1300 W | 1200 W | 1500 W | 1500 W | 1200 W |
| Max. Peak Output | 1500 W | n/a | 1650 W | 1650 W | n/a |
| AC Input | 110 - 240 V | 100 - 240 V | 100 - 240 V | 220 - 240 V | 100 - 240 V |
| AC Voltage Selection | Auto voltage | Auto voltage | Auto voltage | Auto voltage | Auto voltage |
| DC Output +3.3 V | 25 A | 25 A | 30 A | 24 A | 25 A |
| DC Output +5 V | 25 A | 25 A | 30 A | 24 A | 25 A |
| DC Output +12 V (#1) | 50 A | 100 A | 125 A | 30 A | 100 A |
| DC Output +12 V (#2) | 50 A | n/a | n/a | 30 A | n/a |
| DC Output +12 V (#3) | 50 A | n/a | n/a | 30 A | n/a |
| DC Output +12 V (#4) | 50 A | n/a | n/a | 30 A (12V4,5,6) | n/a |
| DC Output -12 V | 0.5 A | 0.5 A | 0.8 A | 0.5 A | 0.5 |
| DC Power +12 V Combined | 1300 W | 1200 W | 1500 W | 1500 W | 1200 W |
| PFC | active | active | active | active | active |
| Specified Hold-Up Time | 17 ms | > 17 ms | n/a | 16 ms | >17 ms |
| MTBF | 100,000 hours | 100,000 hours | 100,000 hours | 100,000 hours | 150,000 hours |
| Cooling Specifications | |||||
| Main Fan | 135 mm | 135 mm | 140 mm | 139 mm | 120 mm |
| Main Fan Speed | up to 1800 rpm | n/a | up to 1200 rpm | 300 - 1000 rpm | up to 2400 rpm |
| Secondary Fan | n/a | n/a | n/a | n/a | n/a |
| Secondary Fan Speed | n/a | n/a | n/a | n/a | n/a |
| Connectors & Environmental | |||||
| 20+4 pin Motherboard | 1x (21.7”) | 1x (23.6”) | 1x (27.6”) | 1x (23.6”) | 1x (24”) |
| CPU | 2x | 2x (26.8”) | 2x (25.6” - 31.5”) | 2x (23.6” – 25.6”) | 2x (25.6”) |
| PCI Express 6-pin/6+2-pin (Graphics) | 0/10x (21.7” - 25.6”) | 0/12x (19.7” – 28.3”) | 0/10x (25.6” - 31.5”) | 0/10x (19.7”) | 0/10x (21.7” - 25.6”) |
| Molex 4-pin (Peripherals) | 6x (19.7” – 31.5”) | 9x (15.7” - 27.6”) | 12x (17.7” – 29.5”) | 10x (17.7” - 35.4”) | 5x (11.8” – 25.2”) |
| SATA Power | 9x (19.7” - 31.5”) | 12x (17.7” - 35.8”) | 20x (19.7” – 33.5”) | 14x (17.7” – 35.4”) | 14x (11.8” – 29.9”) |
| 4-pin Floppy | 1x (37.4”) | 1x (35.8”) | 2x (33.5”) | 2x (41.3”) | 1x |
| Product Specifics | |||||
| Accessories | Screws, Velcro Ties | Screws | Screws, Cable Ties | Screws, SafeGuard, Cable Ties | Cable Ties, Screws, Logo |
| Cable Management | Yes, fully modular | Yes, fully modular | Yes, fully modular | Yes, fully modular | Yes, fully modular |
| Other Details | OC Link | Hybrid Fan Control | Hybrid Fan Control | HeatGuard Extended Fan Run Time, CordGuard Mains Plug Safety Bracket, Twister-Bearing Fan | Hybrid Fan Control |
All PSUs in this test have one thing in common: They are the flagship models of their respective manufacturers. The 1300 W Antec High Current Pro is no exception – no Antec power supply offers more watts. Its efficiency is top notch, too: It is adorned with an 80 Plus Platinum logo. Its power and its price position it in the middle of our test field. In late 2013, we tested its 850 W, Platinum-grade brother, which we liked. Perhaps Antec could have added a hybrid fan control – the 1300 W model doesn’t have it, either, but it does offer 50% more power at identical efficiency. Both models sport four 12 V rails, and you can draw up to 50 A from each of the 1300 W supply’s rails, as long as the maximum power is not exceeded. The 850 W model topped out at 40 A per rail. The high-end model provides a whopping ten 6+2 pin PCIe power cables, sufficient for five high-end graphics cards – Altcoin miners, make a note of it. In addition to that, there are two CPU connectors, nine SATA plugs, and six Molex jacks. If you need more than 1300 W, you can link two of the PSUs with the OC Link, and achieve a staggering 2600 W. It is no surprise that a high-end PSU like this sports fully modular cables, all of which are sleeved. All cable strands are black. Considering the number of cables, the cable lengths seem merely adequate – they are all in the 22” to 26” range. The workmanship is impeccable and high-end materials were used.
| AC Input | 110-240V, 50-60 Hz | |||||||
|---|---|---|---|---|---|---|---|---|
| DC Output | +3.3V | +5V | +12V (#1) | +12V (#2) | +12V (#3) | +12V (#4) | -12V | +5Vsb |
| 25 A | 25 A | 50 A | 50 A | 50 A | 50 A | 0.5 A | 3 A | |
| Individual Output | 6 W | 15 W | ||||||
| Rail Utilization | Sys | Sys | CPU & VGA | |||||
| Combined Output | 130 W | 1300 W | ||||||
| Total Continuous Output | 1300 W | |||||||
| Peak Output | 1500 W | |||||||
Efficiency According to the 80 PLUS Spec
Efficiency for Typical Use Cases

Alas, the Antec HCP-1300 stumbles during the very first round of our lab tests – it simply doesn’t reach the 89 percent efficiency demanded by the 80 Plus Platinum standard. At full load, it tops out at 87.5 percent. We obtained a second PSU sample, but the picture didn’t change, and this discrepancy can’t be attributed to measurement tolerances, either. Even at medium load, the PSU misses the 92 percent goal – however, 91.8 percent efficiency is good enough for us. At 20 percent load, the PSU passes the test. For this test, we also measured the efficiency of all five PSUs at 10 percent load, something which is only required for the Titanium logo. Here, the Antec model achieves 87.7 percent, and at 50 W load its efficiency is a mere 75.6 percent – however, these high-end PSUs are intended for higher loads anyway.
While the Antec PSU’s 22 ms hold-up time is decent, it is only good enough for the second-to-last place in this test field of high-end PSUs – three other high-end PSUs are even better. At a mere 1.28 W, the Antec supply sports the lowest stand-by power draw, but the four other supplies consume barely more power. When we measured ripple and noise, the curves looked very nice on the oscilloscope screen, and the ripple voltages are way below the thresholds.
When it comes to fan noise, the Antec HCP-1300 manages to impress: While its fan is always on, the fan’s sound level only comes in at a low 30.7 dB(A) at all three load ranges (40, 200, and 600 W).
A Closer Look at the PCB
All Antec PSUs are manufactured by Delta, one of the best power supply manufacturers. Unsurprisingly for a high-end PSU, it sports a very modern design with full bridge topology, LLC converter, and DC-DC technology. Only high-end components are used – for instance, the capacitors are from Japan-based RubyCon and Nippon Chemi-Con. While the soldering quality is high, we have seen even better quality from Delta.
The Cooler Master V1200 is brand-new – it was introduced just two months ago, and we immediately tested it back then. But since it fits into this round-up test, we include it here and present our findings once again. At 1200 W, the V1200 and the Seasonic Platinum-1200 constitute the low-end PSUs of this test, which doesn’t mean the V1200 is a low-end PSU: This PSU sports hybrid fan control, which means that the fan can stay off at low to mid-range loads. Choice of materials and workmanship are excellent, and this PSU doesn’t lack features, either. Quoting from our original test: ‘The feature list reads like a letter to Santa Claus. Twelve 6+2 PCIe cables support up to six high-end graphics cards, with PCIe cable lengths ranging from 20” to 28”. Both CPU cables are 27” long, and the farthest peripheral device can be positioned a whopping 36” away from the PSU. However, since you can connect up to 12 devices with SATA plug and up to 9 devices with Molex plug, above-average cable lengths are warranted. The feature set of the V1200 leaves no wish unfulfilled.’ We want to add that all cables are flat, not round.
| AC Input | 100-240V, 50-60 Hz | |||||||
|---|---|---|---|---|---|---|---|---|
| DC Output | +3.3V | +5V | +12V (#1) | +12V (#2) | +12V (#3) | +12V (#4) | -12V | +5Vsb |
| 25 A | 25 A | 100 A | n/a | n/a | n/a | 0.5 A | 3 A | |
| Individual Output | 6 W | 15 W | ||||||
| Rail Utilization | Sys | Sys | CPU & VGA | |||||
| Combined Output | 125 W | 1200 W | ||||||
| Total Continuous Output | 1200 W | |||||||
| Peak Output | n/a | |||||||
Efficiency According to the 80 PLUS Spec
Efficiency for Typical Use Cases

Cooler Master power supplies traditionally sport a single +12 V rail, and this 1200 W PSU is no exception – the +12 V rail of the V1200 can supply up to 100 A. The top-end models from Seasonic and Corsair also have a single rail design – the AX1500i, however, offers mind-boggling 125 A on its +12V rail, 25% more.
Back to the V1200. We already discussed the quality of the V1200 in the previous test. In summary, the PSU rightfully bears the 80 Plus Platinum logo, but at medium load there is not much margin. However, at 20 A and 100 A the PSU surpasses the Platinum spec easily. Unsurprisingly, the efficiency percentages get lower at lower loads – however, 84.4 percent at 85 W isn’t all that bad, this is mid-range in the test field. Allow us to quote the electrical quality assessment from the original test: “We liked the low stand-by power draw of a mere 0.16 W and the long hold-up time, more than 25 ms. The oscilloscope picture of ripple and noise looks nice, and the ripple voltages are, in fact, very low.”
The switch to activate hybrid fan control reminds us of top-end PSUs made by Seasonic, and this is no coincidence: The Cooler Master V1200 is, in fact, manufactured by Seasonic. But there is a minor difference: Seasonic labels the switch positions ‘Hybrid’ and ‘Normal’, whereas Cooler Master opted for ‘Hybrid’ and ‘Auto’, which we find confusing, since ‘Hybrid’ means automatic fan control depending on temperature and power draw. Be that as it may: In ‘Hybrid’ mode, we could not get the fan to turn on at loads of 40 and 200 W, but at 600 W it turned on after 15 minutes, with a pleasantly low sound level of 31.5 dB(A).
A Closer Look at the PCB
The basic layout of the Cooler Master V1200 doesn’t differ much from the Antec PSU, even though the OEM manufacturer is a different one. The V1200 also employs top-quality capacitors from Japan-based Nippon Chemi-Con. The solder quality is excellent. Discussing the input filters in detail exceeds the scope of this test, but they are well-designed on all test candidates.
‘Does it contain a PC?’ was our first question after unpacking the Corsair AX1500i – its depth is a whopping 8.9”, which is comparable to some bare-bone PCs. In other words, please consider the depth of this PSU when choosing a computer case. The power cord of this PSU is specified for 16 A – while most power cords are 10 A models, that wouldn’t be sufficient for plugging this PSU into a 115 V circuit. Assuming that its efficiency is 100%, which even a Titanium-grade PSU can’t achieve, it would draw more than 13 A from a 115 V circuit at design power. By the same measure, the 10 A power cords of the Antec, Cooler Master, and Seasonic PSUs are out of spec on 115 V circuits. While the Enermax Platimax 1500 also came with a 10 A cord, we obtained the European 230 V-only model and, needless to say, only tested it on a 230 V line. Twice the voltage implies half the amps, thus the 10 A power cord is fine for 230 V circuits.
Material quality and workmanship are excellent, but this is true for all high-end power supplies. However, this power supply can differentiate itself with its high efficiency: 80 Plus Titanium – a first in our lab. At the time of writing, the website Plugloadsolutions.com only lists 7 Titanium-grade PSUs: Six models from a company called ‘Super Flower’ and the Corsair AX1500i. We are curious how much more efficient the latter PSU is than the four Platinum-grade PSUs in our test. But let’s discuss its specs first. Its single 12 V rail can supply up to 125 A, 25% more than a single-rail 1200 W supply can muster. Single-rail PSUs have the advantage that you don’t need to plan how to balance the load across the rails. Like Cooler Master, Corsair encloses flat modular cables. The cables are more than sufficiently long, up to 31”. The number of connectors is quite impressive, even though ten PCIe connectors are not the most we have seen in this test. But 20 SATA power plugs and twelve Molex jacks certainly set a new record!
| AC Input | 100-240V, 50-60 Hz | |||||||
|---|---|---|---|---|---|---|---|---|
| DC Output | +3.3V | +5V | +12V (#1) | +12V (#2) | +12V (#3) | +12V (#4) | -12V | +5Vsb |
| 30 A | 30 A | 125 A | n/a | n/a | n/a | 0.8 A | 3.5 A | |
| Individual Output | 32 A | 9.6 W | 17.5 W | |||||
| Rail Utilization | Sys | Sys | CPU & VGA | |||||
| Combined Output | 180 W | 1500 W | ||||||
| Total Continuous Output | 1500 W | |||||||
| Peak Output | 1650 W | |||||||
Efficiency According to the 80 PLUS Spec

Efficiency for Typical Use Cases

Squeezing more and more efficiency from PSU components gets tougher and more expensive as the theoretical limit of 100% is approached. Currently, 80 Plus Titanium is the most demanding efficiency standard – its efficiency requirements at various load percentages are as follows: 10% load – 90%, 20% load – 92%, 50% load – 94 %, and 100% load – 90%. It is obvious that these numbers are not easy to achieve, and the Corsair PSU clearly struggles at medium loads: We measured 93.9%, but we attribute the missing 0.1% to measurement tolerances and don’t accuse Corsair of cheating, especially taking into account that the PSU exceeds all other requirements by at least 1 percentage point. At 10% load, the PSU achieves 90.7% efficiency, and at 85 W still 86.1% - the best results in this round-up test. As the load is reduced further, the Corsair PSU finally falls behind PSUs with lower wattage, but it consistently beats the 1500 W Enermax Platimax. But then again, low-power measurements are almost pointless for high-power PSUs. The hold-up time is more interesting, and the Corsair PSU sports more than 30 ms – outstanding. All other test results are within specs and not very exciting. However, we noted the exceptionally low ripple voltages – a rare occurrence in our lab. Kudos to Corsair!
Like the Cooler Master PSU and the Seasonic PSU, the AX1500i features hybrid fan control, but it cannot be disabled, hybrid mode is always active. The fan slowly begins to turn at approximately 600 W power draw. The key word here is ‘slowly’: You can almost count its revolutions. And it is also very quiet – 29.4 dB(A) is all but inaudible.
A Closer Look at the PCB
Corsair tasked Flextronics with building the AX1500i – Flextronics is perhaps the premium CMS (contract manufacturing service). For a pricey top-end product this makes totally sense, and the outstanding soldering quality reflects this choice. However, the components come from a potpourri of manufacturers: While all primary-side capacitors are made by Nippon Chemi-Con, the secondary-side capacitors were manufactured by Nippon Chemi-Con, Nichicon and Rubycon, and the polymer capacitors by CapXon and G-Luxon - second tier manufacturers. Then again, we don’t worry about the polymer capacitors too much.
Several times already we have included Enermax Platimax PSUs in various round-up tests, and they always impressed us. Enermax sent us the 230 V version of the Platimax 1500, but a 115 V version should be released shortly. Strictly speaking, a 230 V–only PSU may not carry the 80 Plus Platinum logo, only the newly created 230 V version of this logo. This may be the reason why Enermax didn’t try to have the Platimax 1500 certified. At 5 years, the warranty period of this PSU is the shortest in this test – the four other PSUs offer 7 years warranty.
Like other Platimax models, the flagship model sports a nicely built case with roughened surfaces. At a depth of 7.9”, it is also the smallest case in this round-up test – an amazing feat for a 1500 W PSU. By the way, only the flagship model and the 1350 W model have fully modular cabling. While the motherboard cable and both CPU cables are round, all other cables are flat. There are ten PCIe connectors and 14 SATA plugs – impressive numbers, but in this high-end test field only average. The cable lengths are more or less OK, except for the PCIe cables, which are only 20” long.
While Cooler Master, Corsair, and Seasonic embrace the single rail design, the Enermax supply sports 6 (six!) 12 V rails, each of which can supply up to 30 A. This is less than a quarter of the 125 A on the 12 V rail of the Corsair AX1500i. While a fire inspector may favor the 30 A limit, hardware enthusiasts might feel confined by it. We try not to judge, but we deem short circuits and PC fires unlikely.
| AC Input | 220-240V, 50-60 Hz | |||||||
|---|---|---|---|---|---|---|---|---|
| DC Output | +3.3V | +5V | +12V (#1) | +12V (#2) | +12V (#3) | +12V (#4,5,6) | -12V | +5Vsb |
| 24 A | 24 A | 30 A | 30 A | 30 A | 30 A | 0.5 A | 3 A | |
| Individual Output | 32 A | 6 W | 15 W | |||||
| Rail Utilization | Sys | Sys | CPU & VGA | |||||
| Combined Output | 120 W | 1500 W | ||||||
| Total Continuous Output | 1500 W | |||||||
| Peak Output | 1650 W | |||||||
Efficiency According to the 80 PLUS Spec

Efficiency for Typical Use Cases
Since the Platimax 1500 PSU only supports 230 V, it is not eligible for the 80 Plus Platinum logo and we didn’t hold it up to the Platinum standard, either. However, we did compare its efficiency at 230 V to other PSUs at 230 V. At low loads, its efficiency numbers are excellent: At 10% load, it achieves 88.7% efficiency. However, at full load, 88.9% is slightly lower than the requirement of the Platinum standard, while the 230 V input voltage should actually help the PSU in making the numbers. Below 10% load, its efficiency drops precipitously – only the Antec HCP-1300 comes in worse. The other test results are OK, but we think that a hold-up time of a mere 18.5 ms is a tad short. However, this value does comply with the ATX spec. Ripple and noise values are OK, but not as good as the excellent values exhibited by the Antec and Corsair PSUs.
The PSU fan’s sound level, however, is a clear opportunity for improvement. We don’t mind that the fan is always on – the Antec HCP-1300 has shown that this is not a problem. No, the Enermax PSU’s fan is simply too noisy. At a mere 40 W power draw, it generates 34.7 dB(A), which is already quite audible in a quiet room. But at 600 W power draw, the fan’s sound level increases to an annoying 40.5 dB(A).
A Closer Look at the PCB
While most manufacturers position the APFC and the primary side of the PSU on the left side and the secondary side on the right, Enermax rotated this layout by 90 degrees and put the primary side at the front and the secondary side at the rear. Enermax expects better cooling performance from this change, and we concur. Apart from this layout change, the electrical design of the PSU is similar to its competitors, and Enermax uses premium components – the primary side capacitors are sourced from Panasonic, and the secondary side ones are manufactured by Rubycon. The soldering quality is good, but there is some room for improvement.
We could not help but notice that the top model from Seasonic is almost identical to the Cooler Master V1200, which is not surprising since Seasonic manufactures both of them. Their technical specs are all but identical, and the internal layout proves that these two PSUs are twins. But there are minor differences: The number of connectors, cable lengths, and the fan switch’s labels, where we prefer Seasonic’s scheme (‘Hybrid’ and ‘Normal’) over Cooler Master’s. The Seasonic PSU has two SATA connectors more, but two PCIe connectors less and four Molex connectors less. Except from the motherboard cable, all cables are flat ones, and their lengths are similar to Cooler Master’s cables. Like the Cooler Master PSU there is a single 12 V rail which can supply up to 100 A.
| AC Input | 100-240V, 50-60 Hz | |||||||
|---|---|---|---|---|---|---|---|---|
| DC Output | +3.3V | +5V | +12V (#1) | +12V (#2) | +12V (#3) | +12V (#4) | -12V | +5Vsb |
| 25 A | 25 A | 100 A | n/a | n/a | n/a | 0.5 A | 3 A | |
| Individual Output | 6 W | 15 W | ||||||
| Rail Utilization | Sys | Sys | CPU & VGA | |||||
| Combined Output | 125 W | 1200 W | ||||||
| Total Continuous Output | 1200 W | |||||||
| Peak Output | n/a | |||||||
Efficiency According to the 80 PLUS Spec
Efficiency for Typical Use Cases
As expected, the similarities of the Seasonic and Cooler Master PSUs extend to the lab test. The minor differences which did show up can be attributed to parts and measurement tolerances. The Platinum-1200 rightfully bears its 80 Plus Platinum logo, and compared to the Cooler Master V1200, it is all but identical electrically. However, its hold-up time is much longer, thanks to larger capacitors. Ripple and noise are similar – perhaps the voltage curve on the Seasonic is slightly better.
Due to their identical genes, it is not surprising that the hybrid fan control behaves identical on both PSUs: At 40 and 200 W, the fan is off. But when it finally started up at 600 W, we were nonplussed by its noise – 42.7 dB(A) is inappropriate for a high-end PSU.
A Closer Look at the PCB
Since the Seasonic and the Cooler Master PSU are all but identical, there’s not much new to say. The primary capacitors do differ – while the Cooler Master V1200 contains one marked 390uF 420V and a few others marked 330uF 420V, all primary side capacitors in the Seasonic Platinum-1200 are marked 390uF 420V. We saw the effect of this change when we measured the hold-up times of both PSUs
Test Setup
| Test Hardware | |
|---|---|
| AC Source: | Chroma Programmable AC Source 6530 |
| Power Meter: | Yokogawa WT210 Digital Power Meter |
| Loads: | 4x 600 W Chroma 63306 for 12 V testing 4x 300 W Chroma 63303 for 5 and 3.3 V testing using Chroma HighSpeed- DC Load Mainframes 6334 |
| Oscilloscope: | Tektronix DPO3034 Digital Phosphore Oscilloscope (300 MHz) |
| Test Procedure | |
| Voltages: | 110 and 230 V |
| Standby Power: | 0.25 A fixed current to simulate PC standby power on 5 Vsb |
| 80plus Efficiency Testing: | 100/50/20% load, relative to specified total output Load distribution across 12/5/3.3V rails at the same proportion as specified for 100% testing at 110 V according to ATX 2.3 specification |
| Efficiency at Fixed Loads: | 25, 50, 85, 300, 500 W loads Load distribution across 12/5/3.3 V rails at the same proportion as specified for 100% |
| Peak Load Test: | 110% Overload Testing at maximum combined 12 V |
| Temperature Test: | Air intake vs. Outtake temperature delta tracking highest delta during all tests |
Benchmark Results
You can find more test results for these and other PSUs in our Power Supply Charts.
1200 W or more combined with high efficiency – features like these turn a common PSU into a high-end PSU. The five power supplies create an impressive test field: 6700 W total power, the most we ever had in a round-up test. But raw power alone isn’t everything when we talk about PSUs priced above $250. Other criteria, like efficiency, electrical quality, and feature set are similarly important. All five test candidates turned out to be strong, highly efficient power supplies, but we did manage to find a few minor flaws. Let’s look at the PSUs one by one:
If it wasn’t for the tiny 80 Plus Platinum logo, we’d shower the Antec HCP-1300with accolades. But if you talk the talk, you’d better walk the walk, and if you put an80 Plus Platinum logo on your product, you’d better meet its requirements. And the Antec PSU simply doesn’t comply with the 80 Plus Platinum standard, if only at full load – it comes in 1.5% shy of the requirements. Apart from that, the HCP-1300 is a solid performer and its electrical quality is outstanding, although it sports fewer connectors than its competitors. On the other hand, the Antec PSU has a unique feature: You can link two of them together for a total of 2600 W. The fan operates quietly in all load conditions.
The Cooler Master V1200 managed to convince us two months ago when we first tested it, and our opinion hasn’t changed since then. Of course, like the strikingly similar Seasonic Platinum-1200 and the slightly more powerful Antec HCP-1300, it offers less power than both 1500 W supplies. But if 1200 W is sufficient for you, you can’t go wrong with the Cooler Master PSU: Excellent workmanship, a rich feature set, and impeccable electrical quality. The hybrid fan control ensures silent operation at low wattages, but even when the fan operates, it never becomes annoying.
The Corsair AX1500i is not just a high-end PSU – think of it as the high end of the high end. Not only does it offer the extremely high power of 1500 W, it manages to do that with a single 125 A rail. Its depth and weight also exceed anything we’ve previously seen. The Corsair PSU is the first PSU in our lab which bears the coveted 80 Plus Titanium logo, and rightfully so. While its cable lengths are more than sufficient, and there is a large number of connectors, a few other high-end PSUs offer even more connectors. However, its ripple and noise numbers are in a class of its own, and the fan is very quiet when it turns on – at low loads it doesn’t, due to the hybrid fan control feature.
The Enermax Platimax 1500 is an oddball among the test candidates: Right now, only a 230 V version is available, and its warranty period is a mere 5 years. Technically, a 230 V supply cannot carry the 80 Plus Platinum logo. But even at 230 V input voltage, this power supply fails to comply with the 80 Plus Platinum logo requirements at full load. But don’t get us wrong – this is still an extremely powerful, highly efficient PSU with excellent electrical quality. The only thing we didn’t like is the fairly noisy fan.
The Seasonic Platinum-1200 is strikingly similar to theCooler Master V1200. There are but a few differences: The Seasonic PSU sports a longer hold-up time, but its fan is noticeably louder and its price is slightly higher.
















































