Why is Minecraft so slow right now?

Before today my computer could run minecraft at 60 fps using optifine but today when i played i got a constant 5-10 fps. This is not just one single map. Every map has the same low fps. I tried tweaking my settings (i already use super low settings) and it could not change. Is it something with 1.7.10 having problems with 1.7.9 using optifine or is it something else? My computer is brand new just a month old and never had problems with games.