Corsair AX750 80 Plus Gold: Putting Corsair's Best to the Test
by Martin Kaffei on November 30, 2010 12:00 AM EST- Posted in
- Cases/Cooling/PSUs
- Corsair
- PSUs
- 80Plus Gold
- 750W
Conclusion
The Corsair AX750 is the best PSU Corsair sells at the moment, and it shows. It has no problems reaching 80 Plus Gold levels, and with 230VAC it even exceeds Gold requirements. 91% at 50% load is not too shabby.
When you open the Corsair PSU you can see a clean Seasonic design with all solid capacitors from Nippon Chemi-Con, a well chosen line filtering stage in the entrance (Delta), and many surface mounted devices on the PCB. A modern Champion IC in combination with an Infineon switcher are a very common picture for high-end PSUs and deliver a proven quality. ZVS and DC-to-DC are the reason for the high efficiency. Corsair is using the best modern technology, and the AX750 delivers.
Throughout the review, we could only come up with a few minor points of criticism. First, the fan connector could be glued down. Second, the fan grille on the nice black case protrudes a little. About the only real potential concern is trying to utilize all of the Molex and SATA connectors in larger tower cases; you'll want to check the case layout before going that route, although that's definitely a niche market. When that's the worst we can come up with, there's obviously very little wrong with the AX750.
At 10% load Corsair reached 82% efficiency, which is nice to see. Similarly, there is almost no ripple or noise on the rails--+3.3V for example is always under 13mV. The other rails have slightly higher results, but in all cases they're under 20mV. The voltage regulation for +3.3V and +5V could be a little bit better, as both rails drop below 3.60%, but realistically the 12V rail is the important criterion and +12V is just 0.25% under the optimal value.
The delivery contents include 12 SATA connectors on four cables (more than the older Seasonic X-750) and four 6/8-pin PCIe connectors with a black sleeving. The 60cm primary cables are sufficient for most cases, you get two floppy-adapters (just in case), a bunch of cable ties to help you clean up the installation, and flat peripheral cables.
As already mentioned in the introduction, you have to pay more for the older Seasonic X-750 than for the new Corsair AX750. Corsair offers the same quality with flat cables for a lower price. The OCZ Z-Series 80Plus Gold OCZZ850M is no match for Corsair as well, because the efficiency is lower and the soldering quality worse. One potential contender we see is the upcoming HCP series from Antec, which will start at 750W. Otherwise we have to wait for the Seasonic X-760, which should be available shortly.
What we can tell you is that right now, the Corsair AX750 provides a great set of features in a stylish package for a very good price. Yes, you can find less expensive options, and if you get a good sale price you can even get a quality PSU for under $80. However, realistically you're looking at spending over $100 if you want 80 Plus Gold, and not all Gold PSUs are created equal. Silence, performance, quality, and an attractive price make the AX750 very difficult to beat. This is easily one of the best power supplies on the market right now, and for that we're presenting Corsair with our Gold Editors' Choice award. You can get similar performance and quality, but the pricing is usually higher and unless you like waiting to see what the competition can bring to bear, this is a great high-end PSU.
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Nentor - Tuesday, November 30, 2010 - link
"Besides, as we pointed out on the noise tests, the hardware required to even push a 750W PSU to the limits is such that you're likely to idle closer to 150W (or higher)."I am also on the lookout for a high quality build PSU and this point interests me.
Why do these high quality psu always start at around 750W? PSU work most efficient around 50%, as the results in this article also show, so why aren't there any smaller rated ones since idling with it is the most you will be doing?
What about "no-load protection"? When will it kick in on these high end psu?
I probably idle around 120W and wonder if it would be better for the PSU if it has a higher load to work with (relative to its maximum) than almost nothing.
HangFire - Wednesday, December 1, 2010 - link
>Why do these high quality psu always start at around 750W?There are high quality PSU's less than 750W, such as the Seasonic Seasonic SS-560KM 560W. These rarely get reviewed, or submitted for review. Major retailers rarely stock them, especially under 400W. Why? It is a difficult value proposition to get someone to buy a 350-500W power supply for over $100, even though build quality, ripple performance, and hold-up time justify that cost.
The average gamer who just had a 400W cheapie burn out (because it can only produce 200W), then a 800W cheapie burn out (because it could only produce 300W), is finally ready to spend real money for a real power supply. He or She wants 1000W AND quality this time, because clearly 800 (psuedo-)Watts cannot handle a 3.4GHz 920 and single GTX480. But, the gamer cannot afford both Quality and 1000W, so the gamer "takes a chance" with a quality power supply at "only" 750W. Of course, once real quality enters the equation, 600W would be overkill, but that lesson hasn't been learned yet.
>I probably idle around 120W and wonder if it would be better for the PSU if it has a higher load to work with (relative to its maximum) than almost nothing.
The primary difficulty with low-load efficiency is that the 80+ organization doesn't test it, so it doesn't factor into the design because there is no reward for it. The larger a power supply is, the higher wattage the first tier of 80+ testing, since it is percentage based.
A consumer truly concerned with their power bill will purchase a Bronze or Silver with the minimum Wattage rating for their system, rather than a Gold 750 with 400W of excess power. However that is still a difficult value proposition to risk-adverse gamers who have had hardware smoked by the ubiquitous featherweight 400W PSU that came with their first gaming case. For them, excess wattage is insurance.
janwuyts - Tuesday, November 30, 2010 - link
If I compare with your Enermax review from january (http://www.anandtech.com/show/2920) its seems that one is still the better choice no? (quieter and slightly more efficient)Martin Kaffei - Tuesday, November 30, 2010 - link
Hi,well, the Enermax article was written by another editor.
In my opinion Corsair (Seasonic) is better because of very low ripple & noise results, the full modular connection panel and more SATA connectors than the Modu87+ 700W.
In addition Corsair is cheaper than Enermax and Seasonic.
Efficiency is not everything, but you are right. Enermax has some advantages too.
Like the very silent fan control (with a separate supplied hall IC).
JPForums - Tuesday, November 30, 2010 - link
From the article: It would be nice to see some other brands or types; however, all parts are high-quality.(Trying to use quotes causes errors on post)
Why other brands?
Is Nippon Chemi-Con not up to snuff?
You claim they are high quality parts.
The unit is cheaper than its Seasonic counter part, so I doubt cost is the issue.
Why other types?
is there a flaw in this power supplies regulation that would be better served with different parts?
Perhaps there is some other undisclosed reason for your comment. (I.E. Brand Preference)
I'm simply confused as to what information I should be taking away from the above comment.
Is it a subtle hint that Corsair could have done better, perhaps a poorly worded comment that you often see more variation, or something else entirely?
scook9 - Tuesday, November 30, 2010 - link
You mention several times in the article that this is the best Corsair has to offer and I am going to have to disagree......perhaps you meant this family? There is also the AX850 and AX1200.I personally have an HX850 right now and if I ever find the need to upgrade it will be to an AX1200 for sure. That PSU is a MONSTER in both quality and capability. The fact that the AX1200 is less than a cm longer than my HX850 is also AWESOME considering how big alot of competing 1kW+ PSUs are these days
JarredWalton - Tuesday, November 30, 2010 - link
The AX series as a whole is Corsair's current top-end PSU, yes. We only looked at the smallest entrant in the AX family, but it's reasonable to expect similar quality on the higher capacity models. Still, you'd be pretty hard pressed to fully load 750W, let along 850 or 1200W.landerf - Wednesday, December 1, 2010 - link
The AX line isn't all made by the same oem. I'd reword the whole this is the best part. You want to see the best, review the AX1200. It's godly. Also worth noting that quality wise the 850HX beats out a few of the AX models still. I think there's 3 oems for both the HX and AX lines so it's a bit complicated.JarredWalton - Wednesday, December 1, 2010 - link
True there's more than one ODM involved with making the AX series. Seasonic is the ODM for the AX750 and AX850 I believe. The "best" is also up for debate I suppose, but HX850 is 80 Plus Silver and AX is 80 Plus Gold, so in that sense at least it is their "best". Martin is working on a roundup of 1000W+ PSUs, so I'm not sure what's in there but for the uber-PSU folks we have something coming....HangFire - Wednesday, December 1, 2010 - link
All *X series Corsair PSU's are positioned as high-end, versus the -S "gamer" series. The primary difference between AX, TX, and HX is AX is Modular, TX is non-Modular, and HX is semi-Modular.Of course, there are other differences including OEM and 80+ ratings, especially as some models are older than others. Expect more Gold out of TX and HX lines (or their replacements) as new models supersede old.