How to make Minecraft perform better?

Like a lot of people in minecraft, I play to blow sh*t up. I've stacked TNT through the roof and what always ends up happening is my Minecraft keeps freezing. If I've piled together 100+ TNT or more, the screen freezes for a certain amount of time (20 seconds tops) before starting to slowly show the damages done to the area. Other people who I've seen playing are blowing up 1,000,000+ TNT with little or no freeze/lag going on. I've asked people about it and they've told me things like "Oh, you should probably give the game more RAM, not too much though, so I gave the game about almost 3 GB of RAM. No improvement whatsoever. Can anyone please give me some legit info on what I can do to avoid this problem. I've turning all the settings down and disabling a bunch of things on my Windows 8 laptop to try and help it run better, but nothing happens. I have java 64bit which is the one I need exactly to stop errors from occuring.

My Specs (basic)

HP-PAVILION 17 NOTEBOOK PC
Graphics Card: Radeon HD 8650G
Processor: AMD A10 -5750M 2.5GHz (x64 based processor)
RAM: 8GB (7.22 usable)

Added (1). BTW when I don't use a bunch of TNT (50 tops) and just walk around, I run the game around 40-60 fps on max settings.

Well first, make sure your video settings within minecraft are optimized to high performance. Graphics are fast, render distance is about 8, everything is fast.

If you want to go beyond that, download a mod called optifine. There are lots of youtube guides on installing it and other mods.