So my preference is Nvidia however the AMD cards are stated above are performing a little better. I'm confused which to buy and why.
R9 280x-http://www.amazon.co.uk/gp/product/B00FSC5N66/ref=ox_sc_sfl_title_2?ie=UTF8&psc=1&smid=A3P5ROKL5A1OLE
GTX 760 - http://www.amazon.co.uk/gp/product/B00DMB6D8W/ref=ox_sc_sfl_title_9?ie=UTF8&psc=1&smid=A3P5ROKL5A1OLE
R9 280 - http://www.amazon.co.uk/SAPPHIRE-AMD-Graphics-Card-DDR5/dp/B00IRTXPBM/ref=sr_1_1?ie=UTF8&qid=1416853899&sr=8-1&keywords=r9+280
R9 280x-http://www.amazon.co.uk/gp/product/B00FSC5N66/ref=ox_sc_sfl_title_2?ie=UTF8&psc=1&smid=A3P5ROKL5A1OLE
GTX 760 - http://www.amazon.co.uk/gp/product/B00DMB6D8W/ref=ox_sc_sfl_title_9?ie=UTF8&psc=1&smid=A3P5ROKL5A1OLE
R9 280 - http://www.amazon.co.uk/SAPPHIRE-AMD-Graphics-Card-DDR5/dp/B00IRTXPBM/ref=sr_1_1?ie=UTF8&qid=1416853899&sr=8-1&keywords=r9+280