If you dont need that extra juice to have completely everything at ULTRA get the cheaper GTX 750 Ti GPU. If there is almost no price difference def go with the AMD 270x since its faster but usually the 270x is 35-45 pounds more expensive
I can just speak for myself (build a PC for a friend) but
the GTX750 handles BF4 at constant 60FPS (Vsynced) when played at 1600x900 with completely everything set to HIGH (only cutscenes drop to 40).
And since 1440x*900 is 10% less pixels than 1600x900 you can easily set some if not most settings to Ultra.
Since you can keep your memory and your mainboard for the FX6300 you just need to buy the CPU and a GPU.
Total price for both on Amazon.uk = ~ £ 193
http://www.amazon.co.uk/GIGABYTE-NVIDIA-750Ti-PCI-E-Graphics/dp/B00IGQ4UX8/ref=sr_1_1?ie=UTF8&qid=1400290119&sr=8-1&keywords=gtx+750
£114.99
http://www.amazon.co.uk/AMD-FX6300-Edition-4-1GHz-Socket/dp/B009O7YORK/ref=sr_1_1?ie=UTF8&qid=1400290106&sr=8-1&keywords=6300
£77.99
Im pretty sure there is cheaper shops in the UK but I have no idea which ones.
