You might have problems with your computer passing minecraft off to software rendering rather than hardware rendering, I have that problem and in fact still have it because my GPU refuses to minecraft at all. My solution was to crack open my laptop and change the thermal paste, blow out the dust, and eventually I'm adding fans inside the case that blow over the top of the heatpipes and ram...
But you might check to see if you can fix the problem wit ha few clicks, what brand GPU are you using?
If it's NVIDIA like mine: rightclick desktop, click NVIDIA control panel, click manage 3d settings, on global settings make sure it's set to "high performance NVIDIa processor" rather than autoselect which is usually default, then on Program settings select minecraft, or search for the exe if it's not there, then set that to High performance NVIDIA CPU. Click apply and then restart minecraft, see if rthat helps.
Otherwise, install the better optifine as it allows you more control over what you can disable, you might find that certain minor options help significantly.
But before reinstalling try this, set graphics to fast, smooth lighting off, turn render distance down to about 6, max framerate down to 25, advanced open gl to fast, turn off antialiasing and mipmap levels....
You should see a significant difference. Another option that shold help is making chunk loading multicore, you may need to turn off hyperthreading on the NVIDIA control panel in order to make multicore chunk loading work properly..
Good luck,