With just 11 fps you should really get Optifine and tweak the settings, disable particle effects, stars, clouds, swamp colors, and custom sky, set it to Vsync, enable smooth world, fast render and fast math, and set auto save to 30 min. Avoid using resource pack and mods with large numbers of entities (like Mo Creatures and Grimoire of Gaia), allocate 2 GB of memory to Minecraft if you haven't already. Don't play versions 1.8-1.8.6 or 1.9+ as the performance on them is awful 1.8.8-1.8.9 have decent performance for both vanilla and modded, 1.7.10 is slightly better performing (if Fastcraft is installed) and versions such as 1.6.4 and below will generally give better fps.
Aw mo creatures Dx okay, okay I'll do that. I use Windows 7