http://www.palicomp.co.uk/gaming-pcs/phoenix-i5-destiny.html
Bought one from them a couple of years ago.
£650 without Operating system- do you need a monitor?
£600 is going to be a balance between processor, memory and gfx card. Overclockers may well be a better forum to ask - that's full of people who game and can probably give you a better opinion on what the best tradeoffs at the price points are...
You may also find this useful: http://www.videocardbenchmark.net/gpu_list.php to understand raw gfx performance.
dont for get scan.co.uk
Just for another point of view, I'd also get a copy of the latest Custom PC magazine - it has a range of gaming focused PC specs for different price points. It does make a difference whether or not you or your son are comfortable building the PC itself from parts (which generally gives you the best bang for your buck and lets you focus the cash on the bits that make a difference). If he wants Crysis 3 etc, try to reduce specs in other areas if necessary to al least get to a Radeon 7850.
Yup.. Good buy I think.... Should be overclocked as well....Just to let you know what we did. A friend pointed this out to us,
http://www.ebay.co.uk/itm/200904887971?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
Paid £700 for it, EVGA SC GTX670 4Gb and ASUS P8P67 MOBO, Win7 Home Premium.
Did we get a bargain....I hope so