Corsair HX750i Power Supply Review
by E. Fylladitakis on January 14, 2015 10:00 AM EST- Posted in
- Cases/Cooling/PSUs
- Corsair
- PSUs
- HXi Series
Hot Test Results
As the numbers in the following tables depict, the Corsair HX750i offers great power quality and maintains its superb electrical performance when subjected to high ambient temperatures. Our instrumentation recorded a maximum ripple of 40mV on the 12V line, a very good performance figure and slightly better than that of the RM1000 under the same load, despite the fact that both units are based on essentially the same platform. The voltage regulation is excellent, with the 12V line staying within 1.4% and the 3.3V/5V lines within just 1.2%.
| Main Output | ||||||||
| Load (Watts) | 151.88 W | 377.66 W | 563.6 W | 749.05 W | ||||
| Load (Percent) | 20.25% | 50.35% | 75.15% | 99.87% | ||||
| Line | Amperes | Volts | Amperes | Volts | Amperes | Volts | Amperes | Volts |
| 3.3 V | 3.92 | 3.35 | 9.79 | 3.34 | 14.69 | 3.32 | 19.58 | 3.31 |
| 5 V | 3.92 | 5.05 | 9.79 | 5.03 | 14.69 | 5 | 19.58 | 4.99 |
| 12 V | 9.79 | 12.15 | 24.48 | 12.08 | 36.72 | 12.02 | 48.96 | 11.98 |
| Line | Regulation (20% to 100% load) |
Voltage Ripple (mV) | |||||
| 20% Load | 50% Load | 75% Load | 100% Load | CL1 12V |
CL2 3.3V + 5V |
||
| 3.3V | 1.2% | 8 | 12 | 20 | 24 | 10 | 28 |
| 5V | 1.2% | 10 | 14 | 22 | 26 | 12 | 28 |
| 12V | 1.4% | 16 | 22 | 36 | 40 | 38 | 22 |
High ambient temperatures do have a negative impact on the electrical performance of the HX750i, but that impact is relatively small for a 750W PSU. The average nominal load (20-100%) efficiency drops by 0.3% and the maximum efficiency goes down to 94.0% at 50% load. Even though just barely, the Corsair HX750i could maintain its 80 Plus Platinum certification during this test as well, with an ambient temperature over 20°C higher than that of the 80 Plus testing requirements.
Strangely, even with a high ambient temperature, the fan of the Corsair HX750i starts at exactly the same point, meaning that the PSU will operate fanless with a load lower than 300 Watts regardless of the ambient conditions. Once the fan starts however, its speed will increase faster than in the previous test, making the HX750i noticeable with a load of 450 Watts, but the PSU still generates very little noise for a 750W unit even under maximum stress, with a maximum noise level of just under 42 dB(A).
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HollyDOL - Wednesday, January 14, 2015 - link
Please note at what input voltage were the conversion losses and efficiency measured... Usualy 230V tends to be about 2% better than 115V...patrioteagle07 - Wednesday, January 14, 2015 - link
Yup... subpar review... I don't know what I am looking at here.Meaker10 - Wednesday, January 14, 2015 - link
Would help if you read their link on how they measure power supplies rather than repeating it in every article:"Cold Test Results
For testing PSUs, we use 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. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs – 2014 Pipeline post."
(The article links it in the text) they state:
"Our Extech 380803 power analyzer does a very good job at reporting the level of power that our PSU requires at any given time. We should note that all testing is being performed with a 230V/50Hz input, delivered by a 3000VA VARIAC for the perfect adjustment of the input voltage. Unfortunately, we cannot perform tests at 110V/60Hz at the moment, as that requires a high output, programmable AC power source. As a rough estimate, conversion efficiency drops by 1% to 1.5% when the input voltage is lowered to 110V/ 60Hz."
So try reading a bit.
Samus - Wednesday, January 14, 2015 - link
"It appears that Corsair shot themselves in the foot, as there is no reason not to prefer the AX760i to the HX750i, not even if the AX760i is selling at $184 without any rebate, let alone while it is cheaper than the HX750i."This is what happens when you saturate your lineup. Corsair, stop making so many god damn PSU's. You only need 3-4 Categories (80 Plus Bronze, Silver, Gold...and perhaps Platinum) and only a few models in each category. They shouldn't be dividing up the models by modular or fixed cables, either, since this creates inconsistency within the category (the modular category has various 80 Plus ratings!)
For the 80 Plus Bronze: 400, 550, 650 watt
For the 80 Plus Silver: 400, 600, 750
For the 80 Plus Gold: 550, 750, 900, 1200
For the 80 Plus Platinum: 500, 650, 800, 1000
Currently, their lineup is:
http://www.corsair.com/en-us/power-supply-units
They have 8 categories with a dozen products or so in EACH of them. I don't even understand why they have non-80 plus (VS series) products being that they want a reputation of delivering high quality products.
I didn't go to school for marketing, so I'm not an expert at this...but I question whether Corsair's marketing department went to school for marketing...their product lineup is all over the place and there is no consistency.
just4U - Wednesday, January 14, 2015 - link
I'd say cut the silver out all together. Not that it matters Corsair has gotten silly with PSU pricing anyway. Their value lineup is ok but once you hit the $100 mark and on up there are very good alternatives that corsair isn't matching price wise.Lukeroge - Thursday, January 15, 2015 - link
Honestly, AXi (aside from 1500i, which is newer) is worse. It has a pretty cheap mediocre fan, and many units have an issue where the fan makes a tapping sound every 13 seconds at idle. I returned my AX760i and swapped it for an HX850iStrangerGuy - Thursday, January 15, 2015 - link
This particular model that is being reviewed cost a flippin' 140 bucks at Newgg. Do they even know how much better stuff competitors offers at $140? 850W Evga G2 made by the best consumer level PSU OEM, Superflower.AnnonymousCoward - Thursday, January 15, 2015 - link
Love the revieweanazag - Friday, January 16, 2015 - link
I'm not aware of what the Corsair link USB junk does. It would help to cover that as it is a feature that not all PS's have. I'm suspecting it has been covered before in another article; linking that other article would work for me.Another thing I look for in power supplies is if it has two 8 pin 12V ATX CPU cables. Usually it is one 8 plus a 4+4 providing the second 8. This matters if you're going to be able to hook it up to a 2P board for servers. I like to buy power supplies I can use in a desktop or server. This feature can end up costing more like in the Antec HC gamer vs. HC Pro PS's. The Antec gamer lacks this, while the Pro is sporting it.
DanNeely - Saturday, January 17, 2015 - link
Some high end desktop boards are doing 8+4 or 8+4+6 as well; unless you normally replace your PSU with each build, it's something I'd recommend getting when specing out a new PSU for a high end enthusiast system.