Game almost freezes after playing for a while

after playing for about an hour or so my screen freezes for aprox. 6-11 seconds unfreezes long enough to push a button then freezes for another 6-11 seconds. It seems like it is some sort of memory overflow or something because it happens faster if i port into and out of the nether.If I close the Client and re open it it fixes the problem

is it possibly a workspace filling up or not enough RAM? I used to play Minecraft before on the same computer and never had this problem. I recently downloaded it again and started playing and this bug started with my new install.

I looked at the forums for a similar thread and only saw 2 posts regarding FPS, neither posters left any system info so the replies were basically hmm not sure wtf you are talking about.