Looked around on http://www.scan.co.uk/ and just saw this:


http://www.scan.co.uk/Products/ProductI ... tID=368130


A 1.1KW PSU only making 21dB?! That sounds REALLY suspicious...

Does anyone know anything about this?

By the way, there's a 900W version as well.
http://www.scan.co.uk/Products/ProductI ... tID=366220


Here are direct links to the products on Tagan's site, however there's no mention of noise levels there. 1100W alone is an accomplishment, but at only 21dB? Is this really true? Must say I stay a bit sceptical (understatement) until anyone else confirms or denies this. Were they simply measuring a mile away? Or is it at 0% load? Very odd since it seems to be cooled by an 80mm fan. If 21dB is true, it's the perfection of PSUs.

http://www.tagan.com/pages/products/tur ... 0_u95.html
http://www.tagan.com/pages/products/tur ... 0_u95.html

I have a PCP&C 850 SSI myself but I can't use it or they'll soon have to send me to the asylum. But again, 1.1KW @ 21dB would be the holy grail of PSUs if it exists...

Thanks ~ Kris

No. Just no Even if it was really 21dB it would only be at say... 20% load.

Still, that would be 220W (0.2 * 1100 = 220). At 200W even the Seasonic S12-430 is 22dBA. My current Seasonic S12-600 is 25dBA at 200W. Now I'm not sure how dB and dBA compares but at least the numerical value of the Tagan 1.1KW would be four units lower. And four, be it dB or dBA, is a lot!

~ Kris

That 20% figure just popped into my mind, it wasn't an exact figure. Any way it's darn near impossible for it to be 21dB (fan / fan controller).

Tagan have always said figures of 21-22dba on their psu's. My tagan 420w has a similar label on the box, doubt its accurate (psu is fairly quiet, but not that quiet!)

Actually, a change in sound power of 3dB is only barely perceptible by a normal, healthy, human ear. 4dB is not a lot.



At 220W you would be near the bottom of the PSU's efficiency curve. Most PSU's deliver power most efficienly in the middle of their rated capacity (so for this PSU, between 400-700W).



A-weighting

Decibel

In general I recommend you do a lot more reading before you start going around taking manufacturer's specs (actually even the manufacturer is not claiming this level of noise!) at face value. A 1.1KW PSU cooled by a single 80mm fan which emits only 21dB is IMPOSSIBLE.

I would belive it's the start lvl and not anyway nere the max-lvl. Most of Tagans PSUs are rated from 21-28dB so this might be 21-35dB?
Seasonic is 19-37dB or something around that what I can remember.
So it can very well be 21dB at 0% load but not for long

If it's true or not I don't know, I'm just saying it could be

That's really helpful, how many computers do you know can run off a PSU at 0% load?

3dB is almost double the SPL. 4 dB is even more. If we're talking the same type of noise character, the difference between 21dB and 25dB could very well be the difference between inaudible and audible (in a normal room). That's a very big difference to me (then I am VERY noise sensitive).

220W is 20%. Usually you measure efficiencies of a PSU at 20%, 50% and 100%. So it's not an odd number to pick. Still, I'm not sure what point you are trying to make?

Why do you think I started this thread? In my first post I even said this came from Scan UK and not Tagan themselves (Tagan didn't mention noise levels), I even provided the links. Plus, if you know of any reviews of this PSU or other good info to read, please post that!

If it was 99% efficient I would think it is more than possible. Maybe even at 85%+ (194W @ 85%, 122W @ 90%, etc). It's all about the quality of components, heatsinks, fans (there could be multiple quiet 80mm fans pushing the same CFM as a single loud 80mm fan while not emitting nearly as much noise, see stickies in Fan section), size and the rest of the airflow provided. Convection alone could certainly cool the ~11.11W of heat generated by a 1.1KW PSU with 99% efficiency. So this is more a discussion of efficiency I believe. Either way, my system wouldn't tax even 50% of those 1.1KW most of the time, so as long as it's got higher efficiency than my current Seasonic S12-600 and lower noise at all these ranges it'd still be one heck of an upgrade.

~ Kris

Which is a completely moot point since there are no retail PSU's with 99% efficiency, or even 90% (at all loads).



Exactly, so what is the point of getting them. Seems to me you just want to see a big number on the "Rated capacity" sticker on your PSU for ego purposes.

No, my point is you say IMPOSSIBLE while you don't have all the facts. Unrealistic? Perhaps, but impossible? Probably not. Just the same, you focus too much on the rated power or "Rated capacity" sticker on the PSU, while what's really interesting (to me) is efficiency and noise apsects.

Most of the time my system is idle. Right now I'm on a single X1900XTX (yes, my sig is outdated), but if I knew for sure my PSU could handle it I would have gotten myself a CF setup. So, at full load, my system with a X1900 CF would probably peak at much more than 50% of the 1.1kW PSU. Add to this one or two powerful WC pump(s) (Iwaki RD-20 and RD-30) and future proofing the setup.

At 550W (50% of 1.1kW) load my current Seasonic S12-600 would emit 40dBA. Even if the Tagan 1.1kW would emit an extreme 31dB (10dB over claimed spec), even you would surely agree 9dB would be a BIG, tangible and perceivable difference. Add to this an efficiency of, perhaps, 85%, that would save me a lot on the power bill and also make my whole room and setup cooler allowing it to be more silent as well. Efficiency is a very big player for silence, you know.

Even if it was for my ego alone, why would you care? What difference would it make? Now seriously we're at Silent PC review's forums here so if we had the money, we would probably all go to a very far extent in order to reduce noise and heat to a minimum. And that's exactly what I'm discussing here.

You are quite right on the 850 SSI being for my own ego, but I've changed a lot in attitude since then. Back then all I focused on was performance and I completely ignored the noise aspect. Now it's hit back on me and I've become overly sensitive to noise as a result. Believe me, that's punishment hard enough. I used to be able to have the noisiest components you can imagine and not even think about it. Now I can't sit by my dad's ultra-quiet setup I used to think of as completely inaudible without constantly reflecting over how bothered and annoyed I am with the noise emitted, every single second. It's an obsession. A curse.

bear in mind that current manufacturers are making a big deal of their 80%+ rated PSUs, and that there are no 90%+ rating schemes that I'm aware of.

We at SPCR are interested in the efficiency and noise aspects of a PSU but in order to make an objective assessment MikeC has a standard set of tests that stress the PSU across the whole range and it's noted when the rated max power and the measured max power differ.

Probibly none but it was just a theoreticly point. It can be a theoreticly valid claim but not a valid one in reality.
Still, the truth would be 21dB. Pointless but still correct