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[dickiefunk]

Hi,

I’m looking to replace a power supply in my pc as my old one has stopped working.
I’ve been doing some research and the ones I’m considering are a BeQuiet Dark Power 11 550w or Corsair RMx750.

Has anyone had any experience with either/both of these?

What would you recommend around the £100-£120 price?

[ef37a]

I am sure Pete or Martin will be along shortly and I want to know as well!

Dave.

[Pete Kaine]

Both are great as far as stability and voltage delivery go in all the testing results I've seen. My prefered units for audio setups are the L11 series from Be Quiet! or the Seasonic Prime series.

In Corsairs range the AX series would be equal to the two ranges above and indeed is a great range which also tends to be Seasonic built.

The RMx, on the other hand, is a slightly more budget-friendly option along the lines of Seasonics Focus range, although built around a base CWT design, the performance itself tends to be among the better units in the bracket. My gaming guys have used the RMx heavily for years now and we've got tens of thousands of machines out there with them in and the warranty rate is superb, failures over time remain well below market average.

Although with that said, all the ranges I've mentioned above share that quality, as stability over the long term is pretty much the main thing you care about when you need to warranty a system.

[dickiefunk]

Thanks Peter. Is the Be Quiet PSU I listed part of the L11 series?
Which would offer the quietest performance from all the PSU’s mentioned?

[Pete Kaine]

Thanks Peter. Is the Be Quiet PSU I listed part of the L11 series?
Which would offer the quietest performance from all the PSU’s mentioned?

Aye, you listed the Dark Power (L)11 they've just dropped the "L" part from the naming convention these days, old habits and all that, I should have been clearer.

The Dark Power is the quietest, the silent wings fan they use in there is great.

[ef37a]

Don't want to be picky (but you know I am gonna be!) but I cannot see any actual noise figure for that supply?

I do understand however that measuring such low noise levels is tricky and requires expensive facilities.

Dave.

[Wonks]

It's also going to depend heavily on the installation and the amount of power drawn from it.

[ef37a]

It's also going to depend heavily on the installation and the amount of power drawn from it.

Well since it would take quite some setting up and in a very quiet, preferably anechoic room I would think fitting to a representative case and loading to say 80% full whack would be a fairly trivial extra duty? I also doubt whether you could find a sensitive enough SPL meter out side the NPL?

But then, Pete might come back and say. "The supplies are SO quiet that we can't tell whether the friggin' thing is on or off!" If so. NUFF said!

Dave.

[dickiefunk]

Thanks for the replies. I’ve ordered the Be Quiet Dark Power 11 550w.

[Trevor Johnson]

I have a Corsair AX760 PSU, (bought new from Scan), which is effectively silent and very efficient. A very nicely made modular design with a 7 year warranty!

I always think that a bit extra spent on the PSU is well worth it: one of those components which is still useful if you change the MB/CPU etc..

[job]

I always think that a bit extra spent on the PSU is well worth it: one of those components which is still useful if you change the MB/CPU etc..

Also one of those components that can be a potential hazard. Cheap out on anything else and it doesn't really pose an issue. Even a cheap motherboard is fine if you're not overclocking. Cheap PSU? Eek. Not worth the risk i say

[Pete Kaine]

Don't want to be picky (but you know I am gonna be!) but I cannot see any actual noise figure for that supply?

Fan / Cooling technology
Fan type be quiet! Silent Wings 3
+SilentWings ✓
Motor technology 6-pole fan motor
Bearing technology FDB
Fan size (mm) 135
Max. fan speed (rpm), temperature-dependent 1,200
Temperature control for case fans ✓
dB(A) at 20% load 8.7
dB(A) at 50% load 8.9
dB(A) at 100% load 10.1


And yes, the PSU is the last place I'd ever cheap out. I've seen far too many shoddy PSU's blow out and destroy other components. I've seen someone lose their degree dissertation and the back up because the PSU blew a week before it was due to be handed in and it fused both hard drives, terrible position to be in when spending an extra £20 would have prevented it.

[ef37a]

Thanks Pete, I obviously didn't look hard enough!

That is quiet indeed.

Dave.

[Wonks]

I'd prefer to see a dB(c) rating, as there's a lot of low frequency roll-off with A-weighting. You're almost -20db down at 100Hz compared to C-weighting and about -28dB down at 50Hz, so they are probably not quite as quiet as they appear to be.

A 6 pole motor will rotate at 1000RPM, (so at around 16Hz), so a lot of any noise generated will be at low frequencies.

What can probably be said is that of the noise that is produced, very little is above 100Hz. I'm not saying that it's loud at all, but that a noise weighting type has been chosen that promotes the best figure possible.

[Trevor Johnson]

With the Corsair AX760, kitguru, for example, recorded noise from the PSU at <28 dBa for 375W output and the fan only started spinning at 430W. (The kitguru website details the methodology). Incidentally peak efficiency is >93% when output is 50% (as for PSUs in general, they are most efficient at around 50% output).

Mine is a quiet, not silent system, a Noctua NH dual radiator CPU cooler, some case mount Noctua fans, an Nvidia 1080 graphics card, WD black 6TBs, etc.. So the PSU noise makes essentially no difference to system noise.

[ef37a]

How did you come up with 1000rpm for a DC motor Wonks?

I do agree with a C weighting though. The Bquiet has a maximum speed of 1200 rpm and seven blades, that gives a "chop" rate of 140Hz? That is some 15dB below 1kHz on the A scale.

Dave.

[Wonks]

6-pole motor with a 50Hz mains supply. However I was thinking AC and it will almost certainly be a DC motor so you can probably ignore that.

[dickiefunk]

Bouth the BeQuiet Dark Power 550W and it is indeed an extremely quiet power supply!! My PC is now extremely quiet!

[Kypresso]

I've just got a Be Quiet Dark Power 11 750w and very nice it looks as well.

However, i am a bit lost as to which way up to install the psu. I have always installed a psu at the bottom of a case and with the fan facing upwards. If i do it that way with this psu then all the lettering is upside down and on the website there is a video that shows the psu installed with the fan at the bottom with the lettering the correct way up.

One of the things that persuaded me to buy this psu is that it can power the case fans and adjust the fan speeds based on the temperature. If i install it with the fan at the bottom will this still work, i'm assuming that the fan sensor is triggered by the air temperature of the air flowing through the psu and that wont work if the air intake is from outside the case.

The psu is going in a Fractal Design Define R4 case if that helps.

[Pete Kaine]

Personal preference really. I prefer it with the fan pulling air from the case, rather than outside, might as well make use of the extra air flow if we need to have a fan spinning. Admittedly I prefer cases with top mounted PSU's too for that reason (heat rises and all that), but not to the extent that it would stop me using a case with a bottom mounted one if the rest of the design is sound.

However, I don't use the fan controller on the PSU for the rest of the case, as I prefer the fans to be more localized in their control monitoring, so run them off the board BIOS where you can build your own response curves.