Still Experiencing FPS Drops in New SR. Need Help Troubleshooting

So I've gone through some of the troubleshooting that was in the stickied post at the top of this forum(updating sound drivers, video drivers, lowering video settings, disabling vsync, etc), but none seem to alleviate the problem. There was no noticeable improvement with the hotfix either.

In comparison to my laptop and my girlfriend's laptop running the same video settings, my desktop PC sees 10-15 fps lower during major fights. Unfortunately, there isn't a benchmarking program that league can run (like bioshock infinite) where I can eliminate a lot of variables to help troubleshoot the problem, so below is what I've noticed with my eyeballs.

Basically, my desktop can run ARAM(since I can no longer access the old SR) with on all very high settings, seeing FPS drops in the 50's only during the most intense team fights.

On the New SR, on high settings with shadows on low, I get drops down into at least the 30's.

Any thoughts how to improve this would be great. I know my PC runs a fairly old processor(770 GTX video card though), but I would think my system should be better than my laptop.

Attached are my dxdiag files.