RADEON R9 290 4GB GDDR5 256BIT + MINECRAFT = 30FPS-45FPS?

So recently I bought a new PC for making FTB Monster videos, spec:
GPU: Radeon R9 290 4GB GDDR5 256bit
Ram: 16GB DDR3 1866Mhz
Processor: AMD FX-8350 4.2Ghz
Motherboard: MSI A88X-G45
Power supply: Corsair 750W
SSD: 120GB SSD
But at best, when I'm not recording, I'm getting just about 30fps-45fps
I think, that this is because minecraft is not using my gpu, how can I force it to do that?
I can force it to use more RAM, but that almost makes no difference.

Why wouldn't it use your GPU? Your processor doesn't have built-in graphics and your computer wouldn't choose Motherboard on-board graphics over a graphics card.

Minecraft uses only what it needs to calculate the graphic's FPS.

Have you tried minesweeper in win7 you might get lower fps with your MONSTER gpu.