800w PSU powerful enough for these parts?

Which PSU is it? Some models suck and won't actually do 800w.

For a 680 system a good 550W supply will do. Buy Antec, Corsair, Seasonic, XFX. If you are buying other that that ask!

I've never heard of Powercool before, and for that price for an 800w unit, it could be more of a firecracker than you want. There's a reason it's cheaper than all the 800w units you know...

This PSU would do you much better: http://www.amazon.co.uk/XFX-P1-550S-XXB9-PRO550W-Edition-Supply/dp/B004RJ8EKI/ref=sr_1_1?ie=UTF8&qid=1367677236&sr=8-1&keywords=550w+xfx Much higher quality, and you don't need any higher wattage for your setup.

M

^+1 @ marshall.

What nVidia mean is the total system power requirements, and even then they tend to overestimate it by quite a bit so that overclockers and such will never be up against the power limit for their system (stuff like hard-drives and fans draw probably less than 5w each, so can largely be ignored). No one waits to be 30 to buy alcohol because it requires you to be 18. If they say it will run on 550w, given a solid unit you can be 100% sure it will.

Here's a review showing the power draw of a GTX 680 system under very high load: http://www.guru3d.com/articles_pages/geforce_gtx_680_review,9.html 307W is the TOTAL system load (even with a 130W TDP Processor in the test system, whereas your planned system has a 77W Processor), so I wouldn't worry about getting an 550W unit. On the other hand I wouldn't go lower than a trustable 500W unit, since overclocking can up the power requirements by quite a bit.

You only need an 800W for multi-GPU setups, and a proper 800w unit from a reputable brand costs £100+, at the very least.

To use an analogy, you're trying to bring a beat up truck (the 800W unit) to a drag race vs. a sports car (the 550W unit), just because the truck has a bigger engine. You don't need that power, so drop it and invest in quality over quantity. I'd also be surprised even if that power supply can achieve the stated wattage.

On an unrelated note is this system purely for gaming? If so is there any reason for the GTX 680/i7/16GB of RAM over a 7970/i5/8GB?

EDIT: Since you mentioned compatibility, don't go with Corsair Vengeance, it has very high heat spreaders which make it incompatible with the best CPU coolers out there (such as the Noctua DH-14). If you're buying a K series chip I assume you do want to overclock. This is one of my fave kits on Amazon (you can also get it in a 16gb set of 4 like I did) which is faster, cheaper and much more compatible than the Vengeance: http://www.amazon.co.uk/Patriot-2133MHz-Channel-Viper-Memory/dp/B008LTJJI6/ref=sr_1_3?s=computers&ie=UTF8&qid=1367687256&sr=1-3&keywords=patriot+8gb You can also get it in blue, since I seem to see a sort of blue/black theme going on with your build: http://www.amazon.co.uk/Patriot-PVI38G160C9K-Extreme-Masters-Memory/dp/B008MF3R82/ref=sr_1_2?s=computers&ie=UTF8&qid=1367687256&sr=1-2&keywords=patriot+8gb

EDIT 2: Also no SSD? They're really great, every single owner will attest that it's the thing that's sped up their PC the most in the last 5 years. Surely a single HDD would be much cheaper, with the same capacity: http://www.amazon.co.uk/Seagate-ST31000524AS-Barracuda-7200rpm-Buffer/dp/B004HBAGSO/ref=sr_1_2?s=computers&ie=UTF8&qid=1367687463&sr=1-2&keywords=1tb+hard+drive

M

Most people use a combination of ssd+hdd. You put the os on the ssd as well as few key programs that you would like to load quickly and then use the hdd for storage.

Yes 64gb would be enough for that, though if you plan on having any games on it as well I'd recommend going with 120GB (as this allows for a fair few games).

With a 64gb though, after the OS is installed you should have about 40GB for remaining programs. You should always store your personal files on a mechanical HDD.

A good mid-range SSD is the Sandisk Extreme. The 120GB will set you back about £85: http://www.amazon.co.uk/SanDisk-SDSSDX-120G-G25-Extreme-7200rpm-Internal/dp/B006EKJCWM/ref=sr_1_1?ie=UTF8&qid=1367753055&sr=8-1&keywords=sandisk+extreme+ssd There's no 60GB version though. The M4 is a good alternative if you want to go smaller: http://www.amazon.co.uk/Crucial-CT064M4SSD2-64GB-SATA-Internal/dp/B004W2JKWG/ref=sr_1_2?ie=UTF8&qid=1367753526&sr=8-2&keywords=64gb+ssd

At the high end the two great SSDs are the 840 Pro from Samsung and the Vertex 4 from OCZ. 840 Pro: http://www.amazon.co.uk/Samsung-Series-128GB-Solid-State/dp/B009LI7CKI/ref=sr_1_2?s=computers&ie=UTF8&qid=1367753627&sr=1-2&keywords=840+Pro Note this is a very different SSD from the standard 840 non-Pro.

M