Massive Amounts of Lag in 1.9 Update

Minecraft seems to be having an enormous amount of lag in the new 1.9 updates. In Minecraft 1.8.9 and earlier, my game would run at an average 60-120 frames per second. However, in the snapshots and 1.9 prereleases, the lag has been astonishing. My framerate even begins to suffer on the freaking title screen! I'd start up a Super Flat world and get an average of 20-30 frames per second. I'd start up the same world in the previous versions and get quadruple the framerate. It just doesn't make sense, and I don't wish to suffer any longer. I hope this is truly something that can be fixed. Thanks!