I am currently running an E8400 at 3.15Ghz with GTX460 768Mb as a GPU. Trying to run games in 1080p - obviously sacrificing image quality. Would it be a worthy upgrade to replace the GPU with R7 260x 2Gb? I am guessing 2Gb video memory will be much better for 1080p, but am a bit worried about my CPU being a bottleneck in this case. Thank you.