I currently have a prebuilt Asus from 2012. It has a i7-2600 and 8gb of Ram. I also put a GTX 970 in it. Basically as it is getting quite old, it has really slowed down quite a bit and I am having issues with the USB drives. I was curious as to what would be a conservative upgrade to it. Id like to buy a prebuilt PC which is large enough to fit my GTX 970. What would be a logical upgrade, barring anything crazy expensive?