This is my first time building a computer and also the first time I´ve focused on getting a silent/very quiet computer. I´ve been browsing these forums for the last weeks in order to assist me in the component choices and I´ve now come up with the following build (in parenthesis are my second choices):

CPU: i5 3570K - Intending a light overclock to 4.0 Ghz if it does not affect noise too much
CPU Cooler: Noctua NH D-14(or Silver Arrow) - Noctua is a bit cheaper and it seems fitting the silver arrow in the r3 can be hard.
GPU: Asus GTX 670
Memory: Corsair vengeance 16GB Low Profile - 8GB would probably be enough, but as memory is relatively cheap, why not
SSD: 256GB Samsung 830
HHD: 2TB WD Green
Motherboard:Asus P8Z77-V Pro (or Gigabyte GA-Z77x-UD5H or Asus Maximus V Gene) - Prefer the Asus for fancontrol and Gene is not compatible with Noctua NH D-14
PSU: Seasonic X-660 (or Super Flower Platinum Modular 550W) - SuperFlower would be a very good alternative, but I can't find any retailer here in the UK who has it
Case: Fractal design define R3
Case fans:(2x) Noiseblocker Multiframe M12-S2 (or Noiseblocker BlackSilent Pro PL-2 or Scythe Gentle Typhoon 1150 rpm) - Placed at back and top as exhausts, I've chosen the S2's for more flexibility with rpm as it seems the typhoons should be run at full speed

General note: The computer will primarily be used for gaming, and will use two 27" monitors (although I will only use one of them for gaming, and the other for browsing and movies). It will be placed on a wooden floor underneath my desk to the left hand side. Also, I'm primarily concerned with the noise at high/full loads as I think the idle noise is unlikely to bother me.

Questions:
1) How many case fans should I get for sufficient cooling at full load and minimal noise? I'm afraid only 2x exhausts will leave the GPU hot, and loud, under full load. 2x front intakes might be needed?

2) Slightly unsure about motherboard, and I ended up selecting P8Z77 as it received the editors choice here, but not many other Z77 boards have been reviewed. If I don't need the wifi, is the standard version fine too?

3) I think the Asus GTX 670 will be the largest source of noise, would using a custom cooler be significantly better? I'm reluctant to fitting one as from what I hear it's easy to damage the GPU.

4) 660W should surely be fine, but can I go lower? (taking into account the light over clock and that I'm not intending SLI)

Any other feedback is of course greatly appreciated as well!

Will be ordering in a few hours, but hopefully the motherboard and PSU will be fine, and I'll probably end up getting 4x fans and play around.

1) The R3 has a restrictive front airpath. If GPU intake actually becomes an issue, I'd just slap a fan in the side panel vent (or just open the vent). Front just for HDD cooling, if needed. Don't think you'll need 4, but fans are cheap, and then you can experiment better.

2) Standard should be fine too. Fan Xpert 2 is the feature to look out for for SPCR style use. The P8Z77 range overall seems to be very good; I've got the M PRO and it works well, even if it only has Fan Xpert+ and not Fan Xpert 2.

3) Don't like Asus coolers. Of stock coolers, Gigabyte WindForce/Triangle Cool/Whatever they call it now has better reviews for example (relative comparison example here: http://www.xbitlabs.com/picture/?src=/images/graphics/gigabyte-palit-zotac-geforce-gtx-670/75_dnoise-xbt.png). The Gigabyte 670 is affordable to boot.

4) Can go lower with PSU. See here for example: http://www.xbitlabs.com/images/graphics/zotac-geforce-gtx-680-amp-edition/zpw-xbt.png

Other: cooler total overkill for intended use and CPU chosen. Lighter, smaller cooler easier to install and less likely to bend board, lighter case nicer to move around.

Thanks a lot for the input!

1) You are right, better to keep the fans at the side for the GPU, and shouldn't get that noisy as that side will face a wall (I'll keep 5-10cm distance ofc)

2) Great, I'll go for standard and save £20!

3) Seems there's a lot of different opinions on Asus vs Gigabite GTX 670, I just based it off http://www.tomshardware.com/reviews/geforce-gtx-670-test-review,3217-14.html, but you make me leans towards Gigabite

4) Really appreciate that feedback and great link. Not much difference between 550W and 660W Seasonic in terms of price, so I guess primary question is if I can go for the fanless 460W? Going by the table linked it seems so as that processor will take more power than mine, but is it safe to leave such low margin of error?

Yes, the Noctua cooler it probably overkill, you'd suggest Scythe Mugen 3 or something else? From where I'm buying the price difference then would only be £15 though... hm!

1) Be careful not to reflect that noise right back at yourself via the wall. Made that mistake a few times.

2) Lovely. Why pay for extras you won't need; just more drivers and settings and parts to break.

3) I base my opinion on having owned 2 Asus DirectCU cards, both had poor fans that were unpleasant-sounding and had painfully high top RPM. Asus test results/reviews are mixed, whereas Gigabyte's have been positive. I've had my eye on Gigabyte for a long time for active cooling (hence the confusion about the current name they use for the cooling), though I hope to have a passive or "silent type" card next. Right now chugging along with a 100 W system, and the cool ambient is too nice to give up yet.

4) I would stop at 500-550 W (80 Plus). That would be optimal, based on the linked test. The 460 W might work, but it would no doubt run hot when stressed.

Cooler: if you like Noctua, NH-U12P is nice. Have it, love it, CPU idles below 30 °C, does not reach 55 under load I believe. Can go even smaller, but then you may lose out on silence - and you chose a big case anyway.

PS. Read the Tom's review, probably right about that 680 being quiet. I would not extrapolate though, not with Asus. Too much variance over the years for my taste.

Thanks for all the help, seems I'll be fine with some minor modifications and experimentation then!

It will slow down your boot. Why not 8G?

Agreed.

Why not use a Noctua NH C-14 with a single underhung fan.... maybe a 120mm nexus. You can always pump up the fan power later if you want to do so.

Very well, getting a smaller cooler then

The NH-C14 is same price as the NH-D14 though, so might go for NH-U12P as it saves me some money while still being smaller.

The fanless psu and the 560 have the same guts (other than the fan). The 560 is semi-passive design, meaning the fan won't spin for loads less than ~50% and when it does spin up, it's pretty quiet. I push people toward the fanned version - and then you have some cooling if/when you need it. The Be Quiet! Power Pro 10 series is getting rave reviews in the eurozone.

Ordered, thanks for the great feedback!

CA_Steve: you wrote: "The 560 is semi passive..."
Exactly what GPU are you referring to, and what vendor? I ask because that would be perfect.

Just realised CA Steve is talking about the PSU. Thought it was a GPU.. Sorry, my mistake..

By how much?

That's noise vs rpm, shouldn't you be looking for noise vs load or noise vs cooling performance?

Here's the page the chart belongs to: http://www.xbitlabs.com/articles/graphics/display/gigabyte-palit-zotac-geforce-gtx-670_8.html#sect1. To complete the picture, I'll quote: "Our subjective impressions agree with the test results. It is only at 1700 to 1800 RPM that we could hear the beating of one of the impellers but that wasn’t a problem, especially as the card only had such fan speeds while switching from 2D to 3D mode. By the way, the Gigabyte is also the quietest card in 2D mode[...]"

So the cards have indeed been compared in practical scenarios, at least in their nominal modes.

While I agree that data should be presented from practical tests with practical variables, such as noise per load, this is already a good relative comparison, as I mention in the original post. As the reviewer has absolute control over the voltage, this test is no doubt easy to do compared to more experimentation-heavy alternatives. Having tuned my own card cooling for every card I have owned since the 6800 series, I find noise per RPM quite useful information.