People need to stop with this whole thing where they think the graphics card is the be all and end all. For the most part the performance of a game is heavily affected by the ammount of RAM you have as the RAM is what stores all of the temp files, a high core CPU is also needed to increase read and write speeds of those files. Most modern day games need a minimum of 16GB ram these days.
Actually it depends heavily on the game what requirements you need for optimal performance. Sometimes a good high core count cpu is needed, sometimes a good single core performing cpu and a good graphics card and sometimes a little more RAM. The thing with the high core count cpu to increase write and read speeds is not true anymore nowadays. Because even a modern Hard Drive has read/write speeds of around 200 Megabytes a second. If that Hard Drive has some ssd cache the speeds go way up for small files(<100MB or so). Just wanted to clarify that.