Some games are more CPU than GPU intensive and 1080p doesn't really apply a lot of stress to video cards anymore. We're at a point now where low end dedicated video cards and some onboard video can handle 1080p gaming. There's no need to spend large amounts of money building a gaming rig anymore if 1080p that doesn't feel laggy is your only goal. Higher refresh rates will need a bit more of an investment, but 60fps is still doable for not much money. If your video card is being underutilized at 1080p, you should consider 1440p.