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Corsair RM750x PSU Review

Corsair released its RMx PSU line, which the company claims will offer good performance along with silent operation. Unlike the RMi models, the RMx units lack a digital interface, a fan test button, and uses a Rifle bearing fan instead of an FDB version.

Our Verdict

If you don't need the extra bell and whistles of the RM750i and want to save some bucks then the RM750x is a good choice, however the price difference between these two products is small.

For

  • Full power at 49°C
  • Efficient
  • Silent
  • Low ripple
  • Load regulation on the minor rails
  • Quality caps
  • Hold-up time
  • Fully modular
  • Warranty

Against

  • Small price difference with the RM750i
  • Single EPS connector
  • No fan test button
  • Distance between 4-pin Molex connectors

Corsair RM750x PSU Review

In a sudden move, Corsair recently released another PSU series with 80 PLUS Gold efficiency. The RMx models come in five versions with capacities ranging from 550 W to 1000 W. In short, these PSUs are a budget version of the RMi models, designed for users who want high performance without paying the extra cost of a digital circuit. Since the RMx units are based on the same platform that equips the RMi PSUs, they offer good performance along with silent operation. In order to achieve high reliability in these PSUs, Corsair made no compromises in build quality; only Japanese capacitors were used, which last longer than Taiwanese and Chinese versions, and most importantly, they age much slower.

The main differences between the more expensive RMi models and the RMx versions are seen in the latters' lack of a digital interface board and fan test button (which can come very handy on a semipassive PSU). Additionally, the RMx models use a different fan, with a Rifle bearing, which is of lower quality than what the RMi models use. These use fans with fluid dynamic bearing (FDB), which is considered the best bearing available today. Another significant difference is the single +12V rail that the RMx units feature. In the RMi PSUs, the user can choose between single and multi +12V modes through the Corsair Link software.

The following table provides comparisons among the RM, RMi and RMx units.

RMRMxRMi
80 Plus certificationGoldGoldGold
Cable systemFully ModularFully ModularFully Modular
CapacitorsJapanese Primary (APFC)100% Japanese100% Japanese
Max Cont. Output Rating40°C50°C50°C
Fan135mm Rifle Bearing135mm Rifle Bearing140mm FDB
Corsair Link SupportBasic: Monitor fan & +12V loadNoneFull
Wattage Range650, 750, 850, 1000550, 650, 750, 850, 1000550, 650, 750, 850, 1000
Warranty (Years)577
MSRPRM650 - $129.99 RM750 - $139.99 RM850 - $159.99 RM1000 - $189.99RM550x - $109.99 RM650x - $119.99 RM750x - $129.99 RM850x - $149.99 RM1000x - $179.99RM650i - $139.99 RM750i - $149.99 RM850i - $169.99 RM1000i - $199.99

Specifications

The PSU features Gold efficiency, and it can deliver its full power continuously at up to 50 degrees Celsius, like every well-performing PSU should. On top of that, it is Haswell-ready, meaning that it employs independent regulation circuits for the minor rails, and in this case, two DC-DC converters are used. In the section on protection features, we see all of them, since Corsair wanted to provide increased reliability and safety on this platform.

As we already stated, contrary to the more expensive RM750i model, this unit comes with a Rifle bearing fan. Although it is no match for an FDB, it will still get the job done, and it offers good enough reliability. Rifle bearing fans are basically an enhanced version of the plain sleeve bearing ones, offering significantly longer lifetimes, comparable to the lifetimes of ball-bearing fans.

To lower noise output at light and mid loads Corsair included a semi-passive mode, which will also increase the fan's lifetime. Finally, this unit is on the large side, at 18-centimeters long, while its price looks decent given its features.

Power Specifications

Rail3.3V5V12V5VSB-12V
Max. PowerAmps252562.530.8
Watts150750159.6
Total Max. Power (W)750

There is a single +12V rail, which can deliver enough amperes to support a couple of high-end VGAs. The minor rails are very strong as well, while the 5VSB rail is a little stronger than the average, with 3A max-current output.

Cables & Connectors

Modular Cables
DescriptionCable CountConnector Count (Total)
ATX connector 20+4 pin (610mm)11
4+4 pin EPS12V (650mm)11
6+2 pin PCIe (600mm+150mm)24
SATA (400mm+100mm+100mm+100mm)14
SATA (550mm+100mm+100mm+100mm)14
Four-pin Molex (450mm+100mm+100mm)13
Four-pin Molex (450mm+100mm+100mm+100mm)14
FDD Adapter (+100mm)22

A very interesting feature of the RMx units comes in the modular cables they use, which are similar to those of the RMi models and which Corsair describes as Type 4 cables. Polymer capacitors are installed on the +12V, 5V and 3.3V wires of the ATX cable and on the +12V wires of the EPS and PCIe cables, providing extra ripple filtering. On top of that, the ATX cable plugs into the PSU's modular interface through 28 pins instead of the usual 24 pins, with the extra four pins acting as sense wires. The use of sense wires allows for a very tight load regulation, Corsair claims, which is a key performance feature for any high-end PSU.

Power Distribution

Since this PSU features only a single +12V rail, we do not have anything to say about its power distribution.

MORE: PSUs 101: A Detailed Look Into Power Supplies
MORE: How We Test Power Supplies
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Power Supplies in the Forums

  • Blueberries
    I've been promoting these for a while, it's nice to see Tom's do an article on them. The only reason these are Gold rated is because they just miss the Platinum rating at 20%.

    They have a 650x as well that's a little cheaper.
    Reply
  • Amdlova
    High Rate Faliure can be the the name of this series of corsair. for Now EVGA or SEASONIC power supplies. don't spend a penny on corsair products...
    Reply
  • Aris_Mp
    Please keep in mind that some Corsair PSUs are also made by Seasonic. Also this series is very new to have a high rate of failures. Unless you have some solid facts to share on the older RM line which is out for quite some time now.
    Reply
  • jonnyguru
    16801974 said:
    High Rate Faliure can be the the name of this series of corsair. for Now EVGA or SEASONIC power supplies. don't spend a penny on corsair products...

    Wrong on so many levels.

    YOU do not have the failure rate for this or any other Corsair PSU.

    This PSU is the RMx, not the RM, so even if you did have a failure rate, it would only be about two weeks of data.

    If you were talking about the RM and not the RMx, and you actually had failure rate data, you would see that the failure rate on the RM wasn't really high at all.
    Reply
  • PureBlackFire
    High Rate Faliure can be the the name of this series of corsair. for Now EVGA or SEASONIC power supplies. don't spend a penny on corsair products...

    *sigh* nonsense comment of the day.
    Reply
  • chalabam
    Tomshardware:

    I don't know if this is a problem of your site, or my PC/IP, but frequently the charts do not load, even when the page "ends" loading.


    Sometimes, if I "reload", then the charts also load.

    I open all the article pages simultaneously, on different tabs, so I don't need to wait for each one to load.
    Reply
  • Rookie_MIB
    The older RM units weren't 'bad' really, they were ok, but Corsair has been stepping up its game with quality parts and build on some of these newer units which is nice to see. You can never have too many solidly designed units to choose from - competition toughens the breed.
    Reply
  • Blueberries
    High Rate Faliure can be the the name of this series of corsair. for Now EVGA or SEASONIC power supplies. don't spend a penny on corsair products...

    Did you even LOOK at the article? The only problem with these are the Sinopowers on the secondary side, and that's not even a "bad" thing. Oh and btw, some of the best power supplies in the world are Superflower OEMs produced by Corsair.
    Reply
  • mavikt
    With these in depth coverage of PSU's I propose introducing a tier'ing table thing at the and of each review (or perhaps a best buy PSU of the month) equivalent to what's done for CPU's and GPU's, ranking PSU models (perhaps too the makers). I saw a comment here on toms on another PSU news flash in the comment section referring to such thing in the forum but now I can't find it.
    Permanent'ing such thing from the editorial side would be great!
    Reply
  • anort3
    High Rate Faliure can be the the name of this series of corsair. for Now EVGA or SEASONIC power supplies. don't spend a penny on corsair products...

    Did you even LOOK at the article? The only problem with these are the Sinopowers on the secondary side, and that's not even a "bad" thing. Oh and btw, some of the best power supplies in the world are Superflower OEMs produced by Corsair.

    Corsair doesn't use SuperFlower anywhere in its lineup. CWT, Great Wall, Flextronics, Seasonic and Chicony which has since been dropped are all the OEMs Corsair uses or has used.
    Reply