Corsair HX750W - my personal experience

Closely moderated reviews by forum members willing to share their experience and accept stiff peer review. Open only to registered forum members.

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee, Devonavar

Post Reply
Parappaman
Posts: 419
Joined: Mon Aug 31, 2009 12:30 am
Location: Italy

Corsair HX750W - my personal experience

Post by Parappaman » Sat Jan 23, 2010 2:21 pm

Hello people! I want to share some early thoughts on my brand new Corsair power supply, limiting my judgement mainly to its acoustics as none of the reviews around properly addresses this matter. :D

Image

WARNING: text-only down here! Please forgive me as my camera battery died yesterday and have to order a new one when I have time. :cry:


Let me start with a preamble: my PC doesn't need anything even close to 750w of power. In fact, my now retired Enermax Liberty 500w was plenty power for it, as power draw should peak at around 400w including overclock.

Components are as listed:
Motherboard: DFI P45 T2RS JR
CPU: Intel Q8200 OC @ 3,06 GHz, stock 1,2v, passively cooled by a CoolerMaster Z600
RAM: 2x2 GB G.Skill PI 8800 (soon to be 4x2 GB)
Video card: Gigabyte GTX 260 216 sp OC
Storage: WD Caviar Blue 320 GB, Samsung F1 750 GB
Case: Antec Mini P180
Extras: Antec BigBoy fan set to low, Scythe Slipstream 800 RPM, optical drive, card reader.

So why did I get this beast? Well, the Liberty had some major drawbacks I used to convince my wallet to open up and let the cash out.
- Short cables (forced me to buy extension cables to properly route and hide ATX and EPS connector, adding bulk and ugly);
- Low efficiency by today's standard (which makes my ego feel weak, besides wasting power);
- Noise at full load (and a really weird one, as the fan growls like a bear even at slow speed).

The last and most annoying point was "kind of" addressed a year ago with a fan swap. However, I didn't have the knowledge and experience on fans I now have, so I just picked the first 1600 RPM fan (the stock one was a 2000 RPM unit, so I thought it would be a nice compromise) my local store had in stock, which now I can recognize as a Spire sleeve-bearing unit. And I didn't realize that sleeve-bearing fans are not reliable when put horizontally, and cheap ones are even worse, so I ended up with a fan that started spinning only at moderate loads and that topped out at a mere 1000 RPM. Which might sound good noisewise, but the air coming out the exhaust was scorching hot this summer, though only during intense synthetic benchmarking.

And here we come to the way I solved the issue. Spend a little more money on a second fan? That's not reasonable! Spending much more on an insanely powerful unit is. :P

After this unneeded and long preamble, let me start with my little review on this great unit. No, there are no efficiency and noise charts, I don't have any professional instrument to measure such parameters. But I can measure length, and this unit, being no less than 18cm long, is BIG, so it's a tight fit in the P180 Mini that houses my main PC. The dust filter on the bottom had to be moved out of the chassis (it can be mounted two-ways, that's why I love Antec, they thought I could buy this power supply!) and one of the metal tabs holding it had to be cut out (that's why I hate Antec, they make you feel good for finding a hidden feature and then ruin everything by the time you realize you need modding to actually make any use out of it). Once done this, the PSU sled into its place flawlessly.

Let me start with the cables. The undetachable ones are extra long, which is good, but they happen to be extra stiff too, which really isn't, especially when you have to move them through a cramped case like mine. Aside from that, the modular cables are flat, and easily bend in whatever way they have to, and are even longer. An extra word for the included power cord, which is by far the thickest and longest I've ever seen bundled with a power supply.

It's after completing installation that I realized something was missing: the fan RPM header. How on Earth didn't I notice that before? That's a big negative point for me. This is a high-end unit, the reason why such a simple feature was left out of the box goes beyond my knowledge.

I'll have to believe online sources citing a starting fan speed of 930 RPM which, as soon as I powered up the units, seemed consistent. This speed, applied to the double ball-bearing 140mm fan, equals to a power supply that is in no conceivable way silent: airflow is potent, as turbulence noise is. The 25 dBA quote on the Corsair website seems once again consistent.

However, here's where the fun started. Only little tonalities in the noise character (mostly made of broadband turbulence, and a slight, low volume mid-pitched howl) but zero vibrations transmitted, which means that the separated chamber design of the Mini P180 can show its strengths by muffling most of the noise once the side panel is closed. After doing that, in fact, most of the turbulence is gone, and noise character can be compared to the one coming from the rear-mounted Slipstream, which really isn't bad, and is known to be around 19 dBA @ 1 metre in the open. I'm pretty sure that adding the PSU fan to the mix didn't stack up more than 1 or 2 dBA to the baseline noise. Again, too much for a silent PC, but good enough for a quiet one.

And that's just the beginning. Using (obscenely) highly powered units has a lone, but clear advantage over using a properly sized one: the kind of load that the PSU has to withstand is so low that the fan doesn't need to increase its speed. In fact, two hours of OCCT PSU test and several hundreds of wasted watts later, the HX750 was the only thing in my computer that wasn't begging for mercy. Still, the exhaust was just slightly hotter than before.

Conclusions? Well, the Corsair HX750W is a great power supply. Judging by the copious amounts of favorable reviews around, its electric performance is neck-and-neck with the very best around, no matter what. Also, don't forget that this PSU is rated GOLD by the 80Plus organization, but Corsair downgraded spontaneously to a Silver rating just to ensure that every unit around gets the same level of minimum performance. This is simply amazing.

Noise-wise, it can't be used as part of a truly silent PC as its big fan spins just too fast, but it can be added to any high-power rig without significantly increasing its base noise. And its price is really a bargain, as the much famed (though quieter at low loads, and by a few orders of magnitude...) Seasonic X-650w is a whopping 20% more expensive where I live (about €150 vs. €120) and won't leave you the same (hypothetic) upgrade possibilities as the higher powered and better cable-equipped Corsair.

And a 7 years warranty is just... wow! I'll let it blow up in 6 years and get a new one by then! :lol:



That's all folks, I hope this little effort of mine will give you some help to make the right choice when choosing your next power supply! :D
Last edited by Parappaman on Fri Jan 29, 2010 5:06 am, edited 3 times in total.

dhanson865
Posts: 2198
Joined: Thu Feb 10, 2005 11:20 am
Location: TN, USA

Post by dhanson865 » Sun Jan 24, 2010 7:41 am

Interesting. For those that want proof on the Gold rating:

http://www.80plus.org/manu/psu/psu_deta ... =25&type=2

and

http://www.80plus.org/manu/psu/psu_repo ... Report.pdf

and a link to a review which says this is a CWT unit not Seasonic

http://www.hardwaresecrets.com/article/775

Parappaman
Posts: 419
Joined: Mon Aug 31, 2009 12:30 am
Location: Italy

Post by Parappaman » Sun Jan 24, 2010 9:11 am

Added links to the 80Plus testing results (and Corsair's own noise chart) to the first post, thanks! :)

MikeC
Site Admin
Posts: 12285
Joined: Sun Aug 11, 2002 3:26 pm
Location: Vancouver, BC, Canada
Contact:

Post by MikeC » Sat Feb 06, 2010 10:51 am

FYI...

The electrical performance of this unit may be perfectly good, but its acoustics is nowhere near the quietest units we've reviewed. The current benchmark for quiet PSUs is >10 dBA lower than the 25 dBA cited for the PSU by Corsair. 10 dBA is twice/half the subjective loudness... but iirc, my own SPL measurement for this PSU was 30 dBA/1m at idle -- which made it a reject for review, as that's the no-longer-quiet point we defined a long time ago.

Parappaman
Posts: 419
Joined: Mon Aug 31, 2009 12:30 am
Location: Italy

Post by Parappaman » Sat Feb 06, 2010 1:03 pm

Hello my Master, :mrgreen:
That's exactly what I wrote in my post, if you read again...
...a starting fan speed of 930 RPM which, as soon as I powered up the units, seemed consistent. This speed, applied to the double ball-bearing 140mm fan, equals to a power supply that is in no conceivable way silent: Et cetera :D
Of course, as I pointed out in the beginning, I don't have any noise measuring tool, so I couldn't confirm Corsair's claims and will trust yours instead. I also didn't ask for it to be reviewed for the same reason, as I do realize it's a bit out of place here...
But I did want to point out that if the case is good in separating the PSU from the rest of the components and in placing it farther away from the user's ears, then the perceived noise is actually not that bad, and if one also considers the power output, this would be a good enough unit to be used in a high power PC without affecting base noise in any way. Also, it's significantly quieter than my (ex) Enermax Liberty at full load, which I know has never been a silent champion, but whatever... this unit does everything I asked it to, including being quieter at my target load.

And then there's the price... for the quality you get, it's EXTREMELY good value! :wink:

Parappaman
Posts: 419
Joined: Mon Aug 31, 2009 12:30 am
Location: Italy

Post by Parappaman » Sat Apr 03, 2010 12:08 pm

I just ended up exchanging this PSU for an Antec Signature 850w plus a few euros... I guess this Corsair was an even greater buy than I thought, as it allowed me to get this MAGNIFICENT deal! :P

The "new" unit is really on a whole new level noise-wise. I'm wasting some extra watts (I would guess a bit more than 10 at idle) and the added heat can be actually felt, but honestly don't care: finally, the noise floor on my system are the hard drives, again. :wink:

quest_for_silence
Posts: 5275
Joined: Wed Jun 13, 2007 10:12 am
Location: ITALY

Post by quest_for_silence » Thu May 13, 2010 3:55 am

Parappaman wrote:I just ended up exchanging this PSU for an Antec Signature 850w plus a few euros

A few euros? It does sound strange: the Signature costs exactly twice the Corsair!! Where such a deal can be done?

Regards,
Luca

MikeC
Site Admin
Posts: 12285
Joined: Sun Aug 11, 2002 3:26 pm
Location: Vancouver, BC, Canada
Contact:

Post by MikeC » Thu May 13, 2010 8:19 am

Parappaman wrote: I'm wasting some extra watts (I would guess a bit more than 10 at idle) and the added heat can be actually felt, but honestly don't care: finally, the noise floor on my system are the hard drives, again. :wink:
I doubt this very much. No doubt the exhaust air from the new PSU is hotter than from the old one, but this is not due to decreased efficiency, it's just the effect of lower airflow. The Corsair 750 runs cooler because its airflow is probably 3x that of the Signature at idle.

Parappaman
Posts: 419
Joined: Mon Aug 31, 2009 12:30 am
Location: Italy

Post by Parappaman » Tue May 18, 2010 12:43 pm

I would guess the airflow was even more than 3 times the one in the Signature, now that you make me think about it :lol:
quest_for_silence wrote:
Parappaman wrote:I just ended up exchanging this PSU for an Antec Signature 850w plus a few euros

A few euros? It does sound strange: the Signature costs exactly twice the Corsair!! Where such a deal can be done?

Regards,
Luca
It can be done when you find someone with a lot of money and some insane love for a Corsair badge. :mrgreen:

quest_for_silence
Posts: 5275
Joined: Wed Jun 13, 2007 10:12 am
Location: ITALY

Post by quest_for_silence » Tue May 18, 2010 1:17 pm

Parappaman wrote:It can be done when you find someone with a lot of money and some insane love for a Corsair badge. :mrgreen:

Instead I mean it can be done when playing sort of art. 640 c.p.!

Regards,
Luca

ice_v
Posts: 5
Joined: Thu Jan 14, 2010 7:45 am
Location: Italy

Post by ice_v » Tue May 18, 2010 5:21 pm

edit
Last edited by ice_v on Wed May 19, 2010 1:51 am, edited 1 time in total.

quest_for_silence
Posts: 5275
Joined: Wed Jun 13, 2007 10:12 am
Location: ITALY

Post by quest_for_silence » Tue May 18, 2010 9:21 pm

ice_v wrote:Wow...didn't expect replies that fast

Yes, it does seem so: I mean you've wrong thread, and here you're now off topic (the "original" and relevant topic it's the one on the noisy Modu82, not this one on Corsair's review).

However, for the lists, go to SPCR home page, the link "Reference / Recommended" is just in front of you.

Regards,
Luca

Post Reply