There are many Minecraft threads on how to increase the fps. Here are the ones that work and will significantly increase your fps?
First of all, Optifine:
Latest version (1.5.1; 3/22/13): http://optifine.net/...5.1_HD_U_A8.zip Recommended for good quality and good performance: Advanced OpenGL: Fast, Fancy (Doesn't affect fps Significantly) Chunk Loading: Smooth, or Multicore (Even if you have a multicore proccessor Smooth maybe the
best option for you) Details>Trees: Fast (Significantly increases fps while keeping other fancy aspects on)
Add javaw.exe and minecraft.exe as 3D Applications: Go to your graphics card control panel, and do as said. Java is located in C:/Program Files or Program Files(x86) [If 32 bit]/Java/jre7/bin/javaw.exe
Disable dwm.exe: If willing to disable Windows Aero aspects, this will give you a significant fps gain of about 10-20. This is because this service takes up a part of CPU and RAM usage alot for a service running in the background. You can disable this by running services.msc, locating "Desktop Window Manager Session Manager", left click, properties, and "Stop". To prevent from running on startup/boot set "Startup Type" to "Disabled".
Add more ram: If you have a few mods and a 64x-128x texture pack, somewhere around 1024mb of ram would be good. If you have a fairly large amount of mods and/or a very high quality texture pack, 2048mb would go good. Please remember, even if you add more ram to a high quality texture pack, you may still lag!
Here's some ways I recommend you can add RAM: Start up Script: On your desktop, or wherever, Left click>New>Text Document, then rename it what
you like (ex. Run Minecraft). Then right click, Edit, and paste the following in there: