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).

Cold Test Results Final Words & Conclusion
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  • EzioAs - Wednesday, January 14, 2015 - link

    Isn't the fan FDB, not rifle bearing?
  • Galcobar - Wednesday, January 14, 2015 - link

    It is FDB according to the jonnyGURU review in August.

    While Anandtech has a well-deserved reputation for quality reviews, with about 300 reviewed power supplies since 2007 I'll trust OklahomaWolf.
  • djscrew - Thursday, January 15, 2015 - link

    Yep, OklahomaWolf or nothing else when it comes to PSU reviews. Bobnova isn't half bad either.
  • djscrew - Thursday, January 15, 2015 - link

    That being said, Corsair usually ranks from excellent to near perfect for their higher end PSUs like this one.
  • tabascosauz - Thursday, January 15, 2015 - link

    TPU is quite good as well. I'd say OklahomaWolf and crmaris are two of the top PSU reviewers out there.
  • Achaios - Thursday, January 15, 2015 - link

    So, let me get this straight: a. B/c Johnny Guru tested a similar PSU that had an FDB fan and not rifle bearing fan, this review is bad? b. Even if the fan is FDB (wtf is that anyway) and not rifle bearing, how exactly is this the best realization that ever dawned on humanity after penicillin?

    I really don't want some of whatever you are smokin'.
  • Galcobar - Thursday, January 15, 2015 - link

    Because jonnyGURU tested this exact power supply model - and it's 1000W brother - and determined that this had an FDB fan, this review is incorrect in at least one simple area.

    You'll note that nobody in the replies -- other than you -- said this review is bad, or that not being able to identify a fluid-dynamic bearing over a rifle bearing is important in the history of humanity.

    The comments offered opinions on what reviewers do such a good job that they set the standard by which all other PSU reviews are measured. If you have an alternative with equal or greater demonstrated competence, I'm sure the people reading this power supply review would love to have another trustworthy reviewer to consult.
  • Galcobar - Thursday, January 15, 2015 - link

    Bah, typos. Really wish we had an edit button. It's/Its, etc.
  • Lukeroge - Thursday, January 15, 2015 - link

    It looks very similar to the rifle bearing in the RM series, but it's a higher-end FDB bearing like the AX1500i.
  • jonnyGURU - Friday, January 16, 2015 - link

    It's an FDB fan. NOT a rifle bearing. This is stated on Corsair's website and the reviewer's guide included with the press kit. Also, the part number on the fan is different than the rifle bearing used in the RM Series.

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