Extreme frame rate lag caused by new resource packing system

Ever since the new launcher was required to play minecraft and the resource system has changed, my game has been experiencing significant frame rate lag. In version 1.5.2 of the game, i would get anywhere from 60~90 fps with setting on normal render distance and full fancy and smooth lighting. But now that the new launcher is in use, I get 10~20, with all setting on the lowest graphical setting. Even when i switch the version back to 1.5.2 from 1.6.1, the lag persists. That means this is either an issue with the way the launcher works or something with the new way the resource packs and things of that nature.