Corsair RM750 750W Power Supply Review @ [H]

FrgMstr

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Corsair RM750 750W Power Supply Review - We have all read about Corsair power supplies and it is quite likely that many [H]'ers have one in their computer case right now. Today we are looking at Corsair's newest RM series power supply rated at 750 watts. The RM is built, "fully modular and optimized for silence and high efficiency." Let's see how it handles our grueling power tests.


Update - 11/18/2013 - Corsair's newest RM series power supply did not meet up to [H]ard|OCP testing standards and Corsair has been making changes in the PSU over the last month that do address some of our concerns with the PSU and it shutting down under extreme temperature conditions.

This is what we tell our readers in every PSU review we publish: "HardOCP’s testing methodology is intended to very much push power supplies to advertised wattage ratings in temperatures that will represent some of the hottest computer enthusiast cases. So if a unit passes all our testing it is definitely not something to take lightly. In fact we expect more power supplies to fail our testing than make it through unscathed."

Our testing at 45C ambient temperature is the issue with our Corsair RM testing that caused it to fail our internal testing. As we state, that is HOT. We designed our tests this way on purpose. We wanted to put the PSUs we test into a very stressful environment when we test. This way when we make a recommendation on what PSU you should buy, we can make that suggestion and be very comfortable with it. That said, it is highly unlikely that any enthusiast "in the know" would ever see temperatures so high in their custom build even if they only take a few minutes to address proper airflow inside their computer case.

Corsair let us know it was taking measures to address our testing criteria. Here is what it had to say:

The RM Series PSUs, like all Corsair PSUs, are designed and tested using methodologies that closely simulate the environment of an enthusiast/gaming PC under heavy, sustained workloads. Our testing has proven that the cooling system of the RM Series will engage and provide the necessary cooling during heavy real world use.

That said, we’re enthusiasts, too. We understand why Kyle and Paul came to the conclusions they did, and based on their feedback, we’ve implemented a design change that will allow our RM Series PSUs to go the extra mile and endure the extreme synthetic test conditions of the HardOCP test lab.

We have changed the value of the resistor between the thermistor and the fan controller so the fan turns on much sooner than the temperature that would trigger OTP. Therefore the fan should always turn on before OTP is triggered; preventing the PSU from shutting down before it is necessary.

This change has been implemented in all RM PSUs produced since mid October. While we honestly believe even extreme users will never run into the issue encountered during HardOCP’s synthetic test, those end users that want to know if their RM can endure HardOCP’s torture test can identify the updated PSUs by a lot code of 1341 or higher.
Given these changes, we would fully expect the Corsair RM series PSU that we tested to meet our internal testing standards and would earn at the very least a "HardOCP PASS" grade.
 
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While very nice to see that Corsair addressed your review, and may make changes to the way the fan operates it doesn't change the fact that it failed overall. If both units performed similarly that is a good sign it may be one to stay away from, imo the price was a bit too high anyway.
 

Yiffy

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I was a bit surprised they went with Hipro for the RM750. The RM650 was reviewed at Jonnyguru and was built by CWT. Though it had an interesting problem with a couple of it's +5V pins on the ATX connector.
 

[Spectre]

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While very nice to see that Corsair addressed your review, and may make changes to the way the fan operates it doesn't change the fact that it failed overall. If both units performed similarly that is a good sign it may be one to stay away from, imo the price was a bit too high anyway.
Definitely one to avoid. Even if the fan had worked properly this unit is a step backwards from the TX Series units which Corsair reps are now saying are EOL. It is unfortunate that Corsair has chosen to replace the TX units with a worse performing and more expensive product. They seem kind of like a ship without a rudder right now.
 

Cmustang87

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I don't understand why they would replace the TX series with a fully modular option. Wouldn't they want to have less expensive, non-modular options for people who want high watt and reliable PSUs? That is strange.
 

MrMike

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Currently looking to pick up two power supplies before the end of the year, specifically looking for quiet and efficient.

There's more issues with this unit than the fan speed. After reading both this and Jonnyguru's review. The RM series is a complete pass. I can't believe Jonnyguru's site even gave it a 7 in build quality. If I received a power supply with those issues it'd be returned immediately.
 

Modred189

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"Is it going to work today lottery."

AWESOME line. And not awesome if you're corsair. Bummer, since it seemed like a promising unit.
 

extide

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Wow, Corsair seems to be on it's way down a slippery slope! That's pretty unfortunate as they are one of my favorite brands. Commonly known for good quality good looking nice stuff, I hope this product is not a sign of things to come!

Sure makes me happy with choosing the Corsair AX850 psu... (Not that the RM series even existed back when I bought it though) I just went back and read it's review, and man, NIGHT AND DAY compared to this guy!

:eek:
 

MacLeod

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Is it just me or are a lot of Corsair PSU's reviewing kinda ho-hum? Other than the AXi models, I've not seen any real rave reviews on anything from Corsair. They're my favorite brand of pretty much everything they make so I hate to see this when they used to be pretty much the standard bearer.
 

Damn Dirty Ape

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whew. I had just placed an order for an rm750 for my wife's system upgrade. Very glad that Amazon cancel order button was still available.
 

Damn Dirty Ape

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Wow, Corsair seems to be on it's way down a slippery slope! That's pretty unfortunate as they are one of my favorite brands. Commonly known for good quality good looking nice stuff, I hope this product is not a sign of things to come!

Sure makes me happy with choosing the Corsair AX850 psu... (Not that the RM series even existed back when I bought it though) I just went back and read it's review, and man, NIGHT AND DAY compared to this guy!

:eek:
Go take a look at the problems with their h100i hydro cooler and the pump grinding noise. The forum is littered with complaints and has been since it came out. Their standard response is 'get an rma and send it in'.

flash drive
http://forum.corsair.com/v3/showthread.php?t=120540
 
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Oklahoma Wolf

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There's more issues with this unit than the fan speed. After reading both this and Jonnyguru's review. The RM series is a complete pass. I can't believe Jonnyguru's site even gave it a 7 in build quality.
Different models, different OEMs, different issues.
 

maboblivion

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how is running at 50% and ambient temperature "harsh" when at 80% your 20c higher?

*added to psu blacklist
 

MacLeod

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Different models, different OEMs, different issues.
Right. You reviewed the RM650 built by CWT and [H] did the RM750 built by Chicony.

Still a sad statement though that even with 2 different builders, you still get below average results.
 

BigwaveDave

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That sucks, bought one last week. It's been working fine (and quiet) so far, but now I'm not too happy with this shut down issue. 35c ambient....no air flow. Pfft

Trying to RMA it using the links at the end of the article is proving to be a chore so far.

Can't even create a ticket in their system because it isn't added to the hardware drop down list yet.

Grrr
 
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Rattle

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Wow Corsair please take a step back and don't go down this road .... Fuck here we go again
 

MacLeod

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I am well aware of those issues, but luckily they haven't affected me. I own both an H100 and H80.
Yeah that whole pump thing was weird. It was in the H100 's but they eventually got it fixed and if you got a newer model (anything above a certain lot number) like I did, it runs flawless. Then the new and "improved" H100i comes out and we're right back to the pump noise again. I don't get it.
 

SGA76

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I'm guessing the RM part of the name is their sly way of hinting at Return to Manufacturer.
Had it been RMA, it may have been a bit too obvious.
 

Fooshnik

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I like the chamfered corners, I think it makes it look a little more elegant. If I owned one of these I'd send it in immediately whether it's crapped out on me or not. The whole "we were expecting your case airflow to add to the cooling" is nonsense as some cases have the PSU mounted so the fan port is facing outward. Addionally, case air is often warm. ...?

Go take a look at the problems with their h100i hydro cooler and the pump grinding noise. The forum is littered with complaints and has been since it came out. Their standard response is 'get an rma and send it in'.
Well in all fairness, the only thing else they can say is "we're sorry our product sucks, please get an RMA and return it".
 

jonnyGURU

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I like the chamfered corners, I think it makes it look a little more elegant. If I owned one of these I'd send it in immediately whether it's crapped out on me or not. The whole "we were expecting your case airflow to add to the cooling" is nonsense as some cases have the PSU mounted so the fan port is facing outward. Addionally, case air is often warm. ...?
Warm, but not 45°C, which is the temperature Paul tests at. The PSU is advertised as being rated at 40°C.

Also, the PSU doesn't "crap out". The problem would be that the PSU would shut off before the fan turns on, which is a major issue, but is wouldn't be considered "crapping out".
 

Modred189

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Also, the PSU doesn't "crap out". The problem would be that the PSU would shut off before the fan turns on, which is a major issue, but is wouldn't be considered "crapping out".
You might be splitting hairs there...
If the machine turns off because it's fan didn't kick on in time to prevent a heat-related shutdown, or if something on the inside gave out, the PSU still shut off. Any such failure under reasonable or industry standard conditions is not acceptable and could easily, at least in the [H] vein of things, be considered "crapping out".
 

twzTechman

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On my most recent build I was considering a Corsair power supply but am really happy with the SeaSonic I ended up getting. The Corsair h100i not so much. I hope this is not a trend with Corsair products in general as I have usually been happy with their stuff.
 

jonnyGURU

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You might be splitting hairs there...
If the machine turns off because it's fan didn't kick on in time to prevent a heat-related shutdown, or if something on the inside gave out, the PSU still shut off. Any such failure under reasonable or industry standard conditions is not acceptable and could easily, at least in the [H] vein of things, be considered "crapping out".
Well.. could go either way, right? If the OTP didn't trip and the PSU actually overheated to the point of being critical, that would truly be a "crap out". ;)
 

Cmdrmonkey

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Corsair built their reputation by selling high-quality, Seasonic built units, and now they're using that reputation to sell Chinese knockoff garbage at inflated prices. This kind of crap is why I now only buy straight from Seasonic power supplies. Even the "good" brands will sometimes try to pass off bullshit as quality stuff by throwing it in a fancy looking case.
 
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MrMike

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Different models, different OEMs, different issues.
Yep, but that just reinforces my decision to consider the whole RM line off-limits. It's a design issue, both OEMs have quality issues, or a little of each.

Corsair built their reputation by selling high-quality, Seasonic built units, and now they're using that reputation to sell Chinese knockoff garbage at inflated prices. This kind of crap is why I now only buy straight from Seasonic power supplies. Even the "good" brands will sometimes try to pass off bullshit as quality stuff by throwing it in a fancy looking case.
It's the reason you should read reviews per-model and not per-brand or even per-line. As an example, while Seasonic's X-series units are all great you can see that some are better than others looking through the reviews here at [H].
 

Devistater

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Under these conditions, impacted PSUs may shut down before the cooling fan starts spinning. This shutdown will cause no damage to the PSU or the system.
quote from corsair, emphasis added.

So, how the HECK can they say that? Are they guaranteeing that a an abrupt power loss won't screw something on the computer up? Won't cause a hardware failure? Won't cause a software failure? Won't cause a raid failure? Won't cause a windows problem? Awesome, I guess those backup batteries on raid cards for write cache aren't needed then. Are they going to pay to fix anything caused by an overheat and loss of power? If that's the case, man I should put that into my servers because that's a cheap way to get them repaired.

(I'm exaggerating somewhat here to make a point)
 

daglesj

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Corsair built their reputation by selling high-quality, Seasonic built units, and now they're using that reputation to sell Chinese knockoff garbage at inflated prices. This kind of crap is why I now only buy straight from Seasonic power supplies. Even the "good" brands will sometimes try to pass off bullshit as quality stuff by throwing it in a fancy looking case.
Makes you wonder if they have been bought out by a venture capital group or similar.
 

Damn Dirty Ape

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Yeah that whole pump thing was weird. It was in the H100 's but they eventually got it fixed and if you got a newer model (anything above a certain lot number) like I did, it runs flawless. Then the new and "improved" H100i comes out and we're right back to the pump noise again. I don't get it.
I skipped it and went straight to the 110, so far so good.
 

jonnyGURU

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Corsair built their reputation by selling high-quality, Seasonic built units, and now they're using that reputation to sell Chinese knockoff garbage at inflated prices.
FYI: Seasonic is also Chinese.

And if something was a "knock off", that would mean someone was copying someone else's design, engineering, specs, etc.

Chicony's been around a long time. I'd hardly call them a "Chinese knock off".
 

MrMike

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FYI: Seasonic is also Chinese.

And if something was a "knock off", that would mean someone was copying someone else's design, engineering, specs, etc.

Chicony's been around a long time. I'd hardly call them a "Chinese knock off".
True, and so has CWT. I thought of CWT made units as typically being quality also.
 

Modred189

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OH! Or Huntkey! (Or whoever made that horrible Dynex that blew up the testing equipment a few years back.
 

BigwaveDave

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I don't see a big issue with the build quality of the RM series PSU's, just seems to be an issue with the fan waiting a touch too long to come on and causing some heat to build up a little too much. Hopefully a minor tweak and things will be fine?
 

Maineiac12

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I think I'll exchange the RM650 I just bought for a seasonic X650 instead. Only a $10 difference in price.
 

HOOfan_1

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Different models, different OEMs, different issues.
Both are working with less than the ultra quality components that we are used to in Corsair products though. Both seem to be working with lower quality caps on the secondary.

Cost cutting measure perhaps? I wonder what the profit margin on these is versus the TX/TXM series that Paul suggests they are replacing.

Not a fan of the new exterior styling of Corsair, for the past 2 years. Still a fan of their warranty though.
 
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Oklahoma Wolf

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Perhaps a deliberate design decision?
More likely someone at CWT spacing out at the wrong moment.

"Did you remember the jumper for carrying 5V to the larger ATX cable connector?"
"Uh... I think so?"
"Good enough for me. Roll 'em out, boys!"
"Where am I again?"
 

punisher

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True, and so has CWT. I thought of CWT made units as typically being quality also.
CWTs can be very good units (as long as the heatsinks are not loose, right?). The CWT units made for Corsair are/were good units. The old TX and the HX were fine performers. I have an old HX750 (CWT DSG), and it has been flawless for years and numerous builds. I also have a pile of CX430s I have sold over the years, and not a single return. The old TX550 is in my HTPC, and it gets abused by the heat, not a hiccup.

Somewhere somehow someone made a bad decision. Downspecced caps, sloppy QC, and insufficient testing are quick ways to a ruined reputation. Too bad I cannot recommend Corsair PSUs across the board like I used to.
 

Jorona

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I'm not paying premium dollars for a PSU with LTec caps. I won't do it.

This whole unit smacks of quick make some money off the name. Thank you to Corsairs new investor overlords.
 
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