I5 custom gaming pc, need help.

http://www.mediafire.com/view/?wouq1cmlf6knydk

This is the build I'm planning to get, £3.74 over your £900 budget but hey.

The price is without OS, and you can make a bit of money back from selling some games that come with the XFX 7950, or lower the RAM to 8GB instead of 16GB.

Unless you want to use Crossfirex in the future, you could downgrade from Extreme4 to Pro4.

Are you building it yourself? If you are, here are some part i suggest. Includes windows 7 in there, plus a 180GB ssd which is enough to store your OS, games and programs. The 7870 can run any game on high-max settings. Very nice, soundproofed case and quality and reliable PSU. There is overclocking potential due to the k edition core and 212 evo cooler. The z77 extreme4 is an excellent motherboard and has great overclocking tools and potential.

PCPartPicker part list: http://pcpartpicker.com/uk/p/uUlf
Price breakdown by merchant: http://pcpartpicker.com/uk/p/uUlf/by_merchant/
Benchmarks: http://pcpartpicker.com/uk/p/uUlf/benchmarks/

CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor (£161.99 @ Aria PC)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler (£25.45 @ Scan.co.uk)
Motherboard: ASRock Z77 Extreme4 ATX LGA1155 Motherboard (£101.98 @ Dabs)
Memory: Mushkin Blackline 8GB (2 x 4GB) DDR3-1600 Memory (£31.57 @ Aria PC)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£52.20 @ Aria PC)
Storage: Intel 330 Series 180GB 2.5" Solid State Disk (£99.98 @ Novatech)
Video Card: XFX Radeon HD 7870 GHz Edition 2GB Video Card (£191.74 @ Scan.co.uk)
Case: Fractal Design Define R4 (Black Pearl) ATX Mid Tower Case (£89.29 @ Scan.co.uk)
Power Supply: SeaSonic 620W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply (£85.42 @ Amazon UK)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer (£12.98 @ Scan.co.uk)
Operating System: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit) (£69.98 @ Aria PC)
Total: £922.58
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2012-12-30 02:51 GMT+0000)