SeaSonic Platinum Series SS-400FL2 Active PFC F3 400W ATX12V Fanless 80 PLUS Platinum Certified Modular Active PFC Power Supply

Pros: Silent, works (in theory).

Cons: The PSU came with a label wrapped around it that stated it must be mounted in an upright orientation with the top ventilation facing upwards. Since this is a fanless unit, I'm inclined to believe that I really do need to mount it this way for proper airflow.

Unfortunately, the mounting screw holes are situated such that this is impossible. In all of my several tower cases, if I were to mount it with the screws lining up properly, then the unit would be up-side down. In all of my rackmount/media server cases, the unit would be sideways.

I tested the unit in my system and it worked fine, but I had to turn the entire tower case up-side down to be on the safe side.

If proper orientation really is a requirement, then this is a severe design flaw. Very few cases will meet this requirement.

Pros: Absolutely silent. No buzz, no hum, no whine- only quiet, efficient, stable power. Runs cooler than my previous PS, which was a high-end "silent" 800W PS.

Cons: My only gripe is that the included modular, cables are maybe not the greatest looking and feel like cheap plastic (not sleeved).

Other Thoughts: For the price, it performs amazingly. I wish that manufacturers would standardize modular ATX PS cabling, but meh. For the serious modder, you are probably making your own cables anyway.

Keeps my i7 mini ITX system (BF Prodigy) powered solidly.

Pros: The 4-port SATA power cable is fantastic. Each of the connectors reaches a drive in my Lian Li A76 case and there's very little cable between the connectors. If they were available for purchase this would be a 5-egg review.

Cons: Somebody forgot to tell Seasonic that this is a modular power supply and it's going to be knocked for it's quality & selection of cables. I ordered some additional cables from a vendor they recommended and the cables bear no resemblance to the cables that come with the PSU. The cables that come with the PSU are black and are not sleeved. The new ones were colored to match their voltage output and were sleeved.

If you care about aesthetics and plan to use a lot of SATA drives you might be better off trying to build your own cables (18AWG).

Pros: Expensive, but worth every penny. Since installing this in my always-on home server, my power bill has gone down about $10/month. It will pay for itself in about a year and continue to save me money for many years to come. Build quality is extremely high.

Cons: The packaging was ridiculous. Seriously, just pack it in a plain cardboard box and save us the $10.

Pros: Silent!
Modular
Plenty of power for my setup (i3-3220 and a couple HDs)

Cons: Main power cable is pretty stiff--need to pre-flex it into place to install.
Supplementary power cable can't be split, so you have a spare connector hanging out.

Other Thoughts: PSU installed without any problems, other than the aforementioned stiff main power cable.

Basically silent: I can only hear electronic noise if I open the case and put my ear right next to the unit. In fact, it is quiet enough that I can hear my data drive spin down when it sleeps!

I was able to use a single drive power cable by slightly rearranging my drives. Bonus.

Pros: Absolutely dead silent, no squeals or humming.
Runs very cool.
Good assortment of cables and lengths.
Excellent build quality.

Cons: None.

Other Thoughts: Seasonic fanless PSUs are required to be mounted with the top facing up (the side where the fan would normally be) with adequate clearance for ventilation. I did not know this before I bought it.
I was worried that this Seasonic wouldn't work with my case, a Lian-Li with a top mount location for the PSU. When installed there is only around 1/4" - 1/2" clearance between the top of the PSU and the top of the case.
Well, it's working great so far. Everytime I check, the Seasonic is cool to the touch even after the computer has been on all day.

Pros: every sound counts in an audio recording rig, nice to eliminate at least one fan. 3 hard drives, i5 3750k, small vid card, and powers my usb interface no problem. Temjin Series TJ08B-E case helps with the positive pressure design.

Cons: johnny guru review had sleeved cables. must have changed since 2010. i hate those flat ones but i saw pic so i knew what was coming.

Pros: I got this to replace my Enermax Revolution that I had tried to silence by replacing the fan w/ a Noctua (mounted horizontally, the fan induces a buzz due to vibrations into the frame -suppose silicone mounting would help, but ran out of those). The Enermax didn't buzz electrically, but it was only Silver-rated efficient and needed a fan which does.

Now for the Seasonic: it is very much silent in my system. So silent, that you start hearing all sorts of other sounds, like the gentle airflow whoosh from my low-volted fans (vibrations eliminated through silicone mounts, I hadn't tried them on the 180mm fan b-4 thinking it was too heavy, but it isn't and I was pleasantly surprised to have silenced that fan that provides good airflow at ~500rpm) and the noises my LG monitor makes.

Cons: However, when I turn on my Toshiba (i7 1st gen) laptop (which has a very noisy/buzzy and whiny PSU and display inverter), then the Seasonic starts to produce that buzzing (akin to mosquitoes buzzing about your ear, if you put your ear within a foot of the unit) demonstrated on YouTube. If you are further away, it is very faint and hardly noticeable in an appropriately enclosed and insulated case.

Other Thoughts: That said, since I've eliminated the culprit as being my laptop, I now avoid using them concurrently. I know the laptop is the culprit and don't put the blame on the Seasonic, because the laptop induced that same interference and buzzing into my APC power conditioner that I use for my Hi-Fi system (problem solved when separated from same household circuit).

After reading the reviews on the Seasonic, I approached this with the expectation that with voltage regulation running on various systems, there was bound to be some instances where they didn't play well together. And that is what seems to be the case, since some reviews say perfect silence while others note "low electrical noise", and some describe a buzzing. It's down to the mix of devices being used on the same household circuit. If I move my laptop to an outlet on the other side of the room, then it doesn't induce interference and buzzing when run concurrently.

Pros: Finally, not a peep out of my power supply. completely quiet. no sound. how many ways can I say this? I also love that you can choose which cords you need to plug in, so there aren't a bunch of random unused wires that you have to tuck away in the computer case.

Cons: Doesn't fit correctly into my case, which mounts the power supply up top. I was only able to screw one of four screws in... but it seems to be held it place pretty firmly regardless.

Other Thoughts: I WILL be buying from seasonic again; very impressed! perfect for a media computer :D

Pros: Silent, top notch quality and versatility.

Cons: Only 400w, but its fine for my HTPC... Ridiculous lavish packaging. You'd think you just bought a 200 dollar bottle of single malt whiskey... Save the environment ppl!