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Why you might not want to buy a Corsair RM PSU

169K views 652 replies 100 participants last post by  andrews2547 
#1 ·
Before i begin i would like to state this is not a bash or hate thread of any kind, if you want to take it that way and be personal then please dont bother reading this thread, any and all personal attacks will be reported for breaking OCN terms of service.

Last anyone that does not read the OP and just read title of the thread you got no right to complain and anyone that does will be ignored, if you cant keep it civil you will simply be reported and blocked if you cant follow OCN terms of service.
You have been warned.


A link to OCN terms of service.
http://www.overclock.net/a/terms-of-service

One thing i would like to say as is this thread is about ALL! of the RM models not just the 750 and 850 watts as some fools like to think, i am getting very annoyed by people that dismiss this thread without even reading any of it!

If you have an RM its not going to blow up or kill your PC, its not a crappy PSU, but it has some flaws about it which is what i will talk about in this thread.

This time i am going to talk about the Corsair RM series as everyone seems to think this is a great series for a great price

Its really not and am going to talk about it below so please read it all

First problem is price its price in the same area as the Seasonic G series the XFX XTR (which is a fully modular Seasonic G series) the Rosewill Capstone and the semi and fully modular modular Cooler Master V/VS series as well as the Super Flower Leadex/EVGA SuperNova G2/P2

Despite its more money its worse then all of those listed above and i am going to show why, First off there was the well known problem of overheating on the first batch of Hipro/ Chicony Power Technology made units, This has been fixed so no need to beat a dead horse

So lets move on, First thing i want to talk about is the choice capacitors on the RM. Where the Seasonic G has 100% high end japanese capacitors from the likes of Nippon Chemi-Con and Enesol the RM series only has a few on the primary side, But almost every capacitor on the secondary side is Taiwanese Teapo´s and Chinese CapXon´s





So there you have it lower build quality for a higher price below i am going to compare the RM to the
Rosewill Capstone
Seasonic G
CWT made Corsair RM
Chicony Power Technology made Corsair RM
Cooler Master VS
Super Flower Leadex
Cooler Master V

First of is voltage regulation

Lets start with the Seasonic G





Next is the Rosewill Capstone





CWT made Corsair RM





Chicony Power Technology made Corsair RM





Cooler Master VS





Super Flower Leadex





Cooler Master V





Next is ripple

Again Seasonic G



Rosewill Capstone



CWT made Corsair RM



Chicony Power Technology made Corsair RM



Cooler Master VS



Super Flower Leadex



Cooler Master V



Bigest loser ripple wise is the CWT made Corsair RM

Bigest loser voltage regulation wise is the Rosewill Capstone

Last lets compare the platforms same order as before



















Part 2

As said before the 750 and 850 watts RM is not made by CWT but by Chicony Power Technology

Its different then the other models in RM series this is both good and bad







The VRMs use two Taicon electrolytic caps for ripple filtering. All the other caps in the secondary side are by Ltec. Corsair's cap choice definitely isn't the best. Lowering production cost was apparently a prerogative, yet the warranty for this product is still set to five years

The filtering caps in the secondary side are provided by Ltec-not our favorite choice. We think Corsair should use higher quality caps here since this unit usually runs in passive mode. Time will tell if they were right to trust Ltec caps or whether many units will be RMAed instead.

All capacitors on the secondary side is Taicon and Ltec







Soldering quality isn't the best we have seen. The production line probably needs some time to hit optimal quality levels. CWT implementations are clearly superior in this area, so Chicony has some catching up to do. The large metal bar shown on the fourth of the above photos is used to transfer earth to the modular panel, while the smaller bar is used by the +12V rail. We also spotted three current sense resistors right in front of the +12V pads on the modular PCB.

Other reasons

The fan enters the party rather late (allowing for high internal temperatures)
Capacitor choice in the secondary side
Corsair Link USB header not included
Limited functionality of the Corsair Link software (only monitors fan speed and +12V current output)

Part 3

Now i want to talk about the temperatures inside the units as it turns out that the RM runs quite a bit hotter then the units units in this thread, this is due to the low fan speeds the RM fan uses.

Seasonic G


Cooler Master VS


Super Flower Leadex


EVGA SuperNova G2 750 watts


CWT made Corsair RM


Chicony Power Technology made RM


As you can see in those graphs above the CWT made RM actually runs hotter then all the other units does, and this is a unit that uses chinese CapXon capacitors in a closed box with little to no cooling on them, do i really need to say that this is not good?
So there you have it the RM series is overpriced for what you get and you can almost always find better options in the same price range, Why pay more money and get something thats worse then pretty much everything else in the same price range?
Now if they make a huge price drop and its going to be cheaper then the VS / Capstone / G / XTR then it might be worth picking up, But untill then its overpriced for what you get.
Last i also want to talk about how the series that was supposed to be coil whine and noise free have had reports coming in about problems with coil whine, Note that these are few but they are still there, So the coil whine free PSU has coil whine problems talk about irony.
Corsair does give a 5 year warranty on the RM so there is that, But if the RM will last the last untill the warranty ends remains to be seen
The Corsair RM series power supplies are designed to run without active cooling for up to 40% load at typical room temperatures (25°C, or 77°F) and are capable of continuously outputting 100% of output capability at ambient temperatures of up to 40°C (104°F). We have found that our power supplies are typically used in environments much lower than 40°C and tend to have some natural aspiration within the chassis that allows for some air movement, such as from a nearby graphics card or chassis fan, within the PSU housing, when temperatures exceed normal room temperatures. We have found that this normal aspiration can maintain Corsair's Zero-RPM fan-less mode even at temperatures as high as 35°C (95°F) when only at 40% load for durations of up to 15 minutes.

Thanks to recent feedback provided by an early reviewer, we have discovered a PSU fan operation issue that can be triggered with the RM750 and RM850W under highly unusual operating conditions. For the issue to occur, the PSU must be run for more than 15 minutes at:

Ambient temperature 35°C (95°F) or higher
Zero ambient airflow, i.e. no airflow provided by system fans or by fans on other components

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. As these conditions are extraordinarily harsh, we believe most users will not be impacted. If you feel you have a unit that has been impacted, we are offering advance replacement returns for the PSU, with Corsair paying all freight costs. Please click here for instructions on how to obtain a replacement unit, or to ask any questions.

Thank you for choosing Corsair; we are committed to making sure you are completely satisfied with your purchase.

Update - November 14, 2013:
In an effort to improve our products for all of our users, we have updated the RM750 and RM850 to resolve this issue. The thermistor circuit that is used to measure the temperature for the fan controller and OTP has been changed in all RM750 and RM850 PSU's moving forward. An additional resistor has been added that will result in the fan turning on prior to the condition that causes the PSU to shut down in the event that temperatures exceed 45°C
The affected units are in lot codes < 1341 (the first four digits of the S/N.)

Part 4 Techpowerup reviews the 1000 watts Corsair RM and its ripple suppression is rubbish


This is some of the worst ripple i have ever seen on a big brand named unit its worse then even the HighPower made Thermaltake Tough Power Grand and the HEC made EVGA 430/500 and thats pretty shocking.

Quote from techpowerup

The PSU couldn't deliver its full power at or above 44°C-45°C ambient (OTP triggered) over prolonged periods
Ripple suppression at +12V and 3.3V rails was bad
Less than 16 ms hold-up time
Short distance between peripheral connectors
The fan should spin during start-up to make sure it is working properly
 
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#7 ·
Quote:
Originally Posted by korruptedkaos View Post

hey shilka!

you taught me well I think lol
thumb.gif


just a lil thing about the XFX XTR is that is uses a FDB fan too, same as the CM V/VS series psu's
should make it more silent tbh!

so that horrible grinding fan noise on the old core editions with some ADDA fans should be gone on these new units?

wheee.gif
Supposedly yeah.
tongue.gif
Quote:
Originally Posted by sebkow View Post

Corsair PSU's have never been very good from the hardware to software. Im surprised people still buy them. Always so many problems.
Noted
tongue.gif
 
#8 ·
Quote:
Originally Posted by sebkow View Post

Corsair PSU's have never been very good from the hardware to software. Im surprised people still buy them. Always so many problems.
This is not completely true, in fact their PSU's have been a very reliable source for builds for years, it is just their current choice of OEM partner that is bad.
There is nothing wrong with my outgoing TX750 apart from a little coil whine on my unit.
I am in fact totally amazed that I have bought a CoolerMaster after the flames pops and dead motherboards from years gone by.
 
#9 ·
Quote:
Originally Posted by BakerMan1971 View Post

This is not completely true, in fact their PSU's have been a very reliable source for builds for years, it is just their current choice of OEM partner that is bad.
There is nothing wrong with my outgoing TX750 apart from a little coil whine on my unit.
I am in fact totally amazed that I have bought a CoolerMaster after the flames pops and dead motherboards from years gone by.
not all are bad! there just too pricey & tbh I cant stand them! the only positive thing about corsair PSU's is that they made me actually give a damn who makes it & how good it actually is!

thx for opening my eyes corsair
lachen.gif
 
#10 ·
Well I am in the UK and their prices for the units I have bought in the past have always been comparable to other quality brands.
Comparing Corsair to some other brands, I would say they were quite fair.

I do wonder why Corsair have chosen to take that path though, and the original comment from Shilka does stand. the RM while well reviewed is just not as good as the immediate competition, not to mention the glaring build mistake, is that isolated? or has it been corrected?
 
#11 ·
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#13 ·
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#14 ·
Part 2

As said before the 750 and 850 watts RM is not made by CWT but by Chicony Power Technology

Its different then the other models in RM series this is both good and bad

The good news is the 5v bridge has not been forgotten so no problems with dead 5v pin on the 24 pin ATX cable

The bad news is this





The VRMs use two Taicon electrolytic caps for ripple filtering. All the other caps in the secondary side are by Ltec. Corsair's cap choice definitely isn't the best. Lowering production cost was apparently a prerogative, yet the warranty for this product is still set to five years

The filtering caps in the secondary side are provided by Ltec-not our favorite choice. We think Corsair should use higher quality caps here since this unit usually runs in passive mode. Time will tell if they were right to trust Ltec caps or whether many units will be RMAed instead.

All capacitors on the secondary side is Taicon and Ltec







Soldering quality isn't the best we have seen. The production line probably needs some time to hit optimal quality levels. CWT implementations are clearly superior in this area, so Chicony has some catching up to do. The large metal bar shown on the fourth of the above photos is used to transfer earth to the modular panel, while the smaller bar is used by the +12V rail. We also spotted three current sense resistors right in front of the +12V pads on the modular PCB.

Other reasons

The fan enters the party rather late (allowing for high internal temperatures)
Capacitor choice in the secondary side
Corsair Link USB header not included
Limited functionality of the Corsair Link software (only monitors fan speed and +12V current output)
 
#15 ·
I have just read the review over on Mr Guru's site, who notes that despite the use of controversial caps, Chicony are capable of making even the worst caps last forever.
Oklahoma Wolf did mark them down for those caps though as that is the scoring system. The Supply received a solid 9.2 in the review, so we need to keep things in perspective.

Thoughts?
 
#16 ·
Quote:
Originally Posted by BakerMan1971 View Post

I have just read the review over on Mr Guru's site, who notes that despite the use of controversial caps, Chicony are capable of making even the worst caps last forever.
Oklahoma Wolf did mark them down for those caps though as that is the scoring system. The Supply received a solid 9.2 in the review, so we need to keep things in perspective.

Thoughts?
I dont like cheap caps to me thats just feels cheap lazy and a weak spot that could be avoided
 
#17 ·
Of course these crappy cap companies are like anyone else and can improve over time, which was hinted on the JG review,
I do of course agree that Corsair have taken a step backwards here and informing people of this is important, however we need to try to avoid sweeping statements about a company based on a few products.
 
#18 ·
Quote:
Originally Posted by BakerMan1971 View Post

Of course these crappy cap companies are like anyone else and can improve over time, which was hinted on the JG review,
I do of course agree that Corsair have taken a step backwards here and informing people of this is important, however we need to try to avoid sweeping statements about a company based on a few products.
I dont think everything Corsair sells is bad but they do have some things that are not worth buying

The CX CS RM and AXi PSU series are what i believe are not worth buying

Note they are not worth buying for the same reasons

NZXT has gotten so much flak form me for pushing out the HALE 82-N and V2 but no one cares when i talk about that

As soon as i start talking about Corsair all the fanboys screams bloody murder
 
#19 ·
It´s a travesty that Corsair doesn´t do a recall on those kinds of units. They are afraid of damaging their rep. My dad has a BMW, he went for some kind of repair and the mechanic said "hey that model needs a new radiator, the existing ones are faulty etc.". No official announcement from BMW, if he had never gone there himself to fix an unrelated problem with the car he wouldn´t have gotten the new radiator, because BMW doesn´t do official recalls like that. Same thing with Corsair etc. Most people with those PSU´s will never know about this and they will wonder why their system isn´t working.
 
#20 ·
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#21 ·
Let's set aside companies and which products are which and look the problems experienced. They're not all the same.

Problem 1: faulty fan control algorithm causes power supply to shut down by reaching OTP limit when operated constantly around 50% load (but not high enough for the fan to kick in) with high enough ambient intake temperatures and the right conditions. Doesn't seem to affect most users based on usage patterns and not seen by most reviewers even stress testing 40% load in hotbox.
Fallout: hardware revision so new units shipped have the problem fixed. Replacements for old users available and with free shipping.

Problem 2: not enough insulation on a thermal pad causes some samples to shut down or not be able to power on. Wasn't seen by reviewers.
Fallout: hardware revision so new units shipped have the problem fixed. Replacements for old users available and with free shipping.

Problem 3: missing wiring causes some +5V pins on ATX connector to be unused. This results in effectively less power being able to be supported for the motherboard on a +5V-based system. Doesn't affect people using systems newer than Pentium 3 or so.
Fallout: ?? I don't know if there's a hardware revision or not, but there's no recall I think.

I don't think problem 3 is worth the hassle of changing out for most users, since it's not an issue for almost everybody. Got that Pentium 3 overclocked? Problem 2 seems the most serious as that affects the operation of potentially every unit no matter how you use it, so it should get the most aggressive response. I'm not sure if the shipping details / RMA / returns process was a little different on 1 and 2.
1 was the old Corsair RM750/850 issue, and 3 was on the other RMs (maybe not 1000W? I'm not sure). 2 was EVGA 1000W/1300W Leadex-based power supplies.
 
#22 ·
The problem with the missing +5v connectors is far more serious than the other 2 actually.

Not all motherboards are made the same way. A lot of components work using very low voltages, below 2 volts, with mosfets on the board doing the conversion by using the major lines. One manufacturer might be using the 12v line to provide low voltages, some other might be using the 5v line while some other the 3.3v line.

Now, the thing is. It's certain that some boards use the +5v line to feed some fets with power. When some of the 5v connections are missing then the board either shuts off, (that's bad) or overloads the other 5v connections (that's even worse, this means that your system will be set on fire).

The end result is some boards frying themselves, while most others are not. All because of the PSU being off-specs. But the end user will not know that the PSU is responsible (unless he knows that this specific PSU line has this specific issue) and will en up blaming the motherboard manufacturer.
The worst part is, that because of Corsair's reputation, it'll be impossible to convince the end user that the PSU is to blame.

Yeah, it's that bad. Way to go Corsair.
thumb.gif
 
#24 ·
Quote:
Originally Posted by mikeaj View Post

Some FETs maybe but not CPU VRM FETs, unless you know of some examples? You shouldn't be getting enough draw to be a concern from the other components on the board outside of CPU power delivery.
Memory VRM and alot of 5V stuff on a mobo. If you're ignorant to that then I guess you read up
 
#26 ·
Quote:
Originally Posted by PsyM4n View Post

If the motherboard maker decided to use the 5v line to power the ram, pci-e, pch/southbridge and the rest "secondary" fets you're pretty much screwed actually.
Any boards out there right now that does?
 
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