Dear Sir,
I wish to purchase a PSU for my system. With the help of PSU finder was able to find PSUs in the range of 500-650 W. I was unable to determine which one was best for me. I want the "QUIETEST" PSU for my PC. Please note:-

1) I never overclock my system and always run all components at stock voltages and prefer doing so in future as well.
2) The maximum TDP of my i7 processor is 130 W.
3) The maximum power consumption of my graphics card is 100-110 W.
4) Other specifications are:-

Motherboard:- Intel DX58SO Bloomfield 45 nm architecture
Processor:- Intel i7 920 2.66 GHz LGA 1366 socket
RAM:- 6 GB DDR3 Transcend 1066 MHz
Video card:- PowerColor HD 7850 2 GB DDR5
Hard Drives:- Seagate 2 TB 5900 rpm and Seagate 500 GB 7200 rpm
Optical Drive:-SONY DVD RW
Case :- Corsair Carbide 300R

Price of the PSU does not matter. The only thing that matters is (yes, I know I am repeating it) that it should be "completely silent".
Please advise.

Seasonic x-560 and Kingwin LZP-550 are semi-passive. Passive at loads less than 50% or so. Then quiet fan ramping up after that. Either are a good fit for a gaming PC. Both series are reviewed here.

Another option, if 500W is enough... KINGWIN STR-500 500W ATX 12V v2.2, EPS 12V v2.91 and SSI EPS 12V v2.92 SLI Ready 80 PLUS PLATINUM Certified Modular Active PFC Stryker Fanless Power Supply, also reviewed here, Fanless PSUs: Kingwin Stryker STR-500.

If you need a little more W, then go with the LZP, as previously sugguested by above poster. I would probably avoid Seasonic, although i have no issues with mine, and i do recommend them, i seen some people with issues with buzzing, so i would go with Kingwin.

For power consumption, beware that PSU calculators always overestimate. Your system will probably use around 300W max.

If you can wait just a few weeks then there is the Seasonic Platinum 400, 460 and 520 which are all fanless. MikeC is reviewing a 520W now...

Thank you everyone for their valuable suggestions.
However, I am staying in India and the Kingwin PSU is not sold anywhere in India. I also checked on the internet but was neither able to find an authorized distributor nor a retailer. Please could you let me know the other "QUIETEST" PSUs which may be available in India so that I could purchase them.
I shall be highly grateful.

It might be helpful for you to know that the Kingwin Lazer Platinum series is based on the Super Flower Golden King platform, so if the Super Flower brand is available to you in India, that is one possible solution.


According to their respective websites the Seasonic X series is fanless up to 20% load (+/- 5%). While the LZP series is fanless up to an internal temperature of 65/70C.

That info is a bit misleading -- not you Garak, but Seasonic. If that is indeed what Seasonic states, the first statement is based on extrapolation from temperature/load data. The second statement is probably accurate.

AFAIK, every PSU uses thermal monitoring to control the fan, not power or current. The latter is used for overload protection, but for fan control, thermal sensor control is the rule. There are no exceptions among consumer computer PSUs. (Among enterprise server/workstation PSUs, there may be exceptions.... but I don't know of any.)

A quick search shows Seasonic is indeed available in India: http://www.primeabgb.com/index.php?opti ... &Itemid=53

Hello Mike C.
This is the image which Seasonic uses to describe their “Hybrid Silent Fan Control” design, and which I based my statement on:
http://www.seasonicusa.com/images/X/X-04.jpg

And a survey of X-bit labs reviews of the X series (X-750, X-560, X-660, X-760, X-850) shows them starting up at ~150W, my maths tells me that this is 20% (+/- 5%) of each unit's capacity.
http://www.xbitlabs.com/articles/cases/ ... p-2_3.html
http://www.xbitlabs.com/articles/cases/ ... nic_9.html
http://www.xbitlabs.com/articles/cases/ ... dup_6.html

It also seems likely to me that Seasonic is using thermal fan speed control, but it still coincides with 20% load (rather than 50% load) based on the info I have seen.