These are similarly price but which performs better?
http://www.shop.bt.com/products/sapphire-technology-amd-radeon-r9-270x-1020mhz-4gb-gddr5-pci-e-3-0-hdmi-oc-90P0.html?refs=55570000-55120000
http://www.shop.bt.com/products/sapphire-technology-amd-radeon-r9-270x-1110hz-2gb-gddr5-pci-express-3-0-hdmi-toxic-90N1.html?refs=55570000-55120000
http://www.shop.bt.com/products/sapphire-technology-amd-radeon-r9-270x-1020mhz-4gb-gddr5-pci-e-3-0-hdmi-oc-90P0.html?refs=55570000-55120000
http://www.shop.bt.com/products/sapphire-technology-amd-radeon-r9-270x-1110hz-2gb-gddr5-pci-express-3-0-hdmi-toxic-90N1.html?refs=55570000-55120000