Who said you can't have good fps wilst still having amazing visuals? big pixles cobines a 8,8 texture pack(brilliant for slow computers) and a high def look. This pack also eliminates fire and portal animations, this dremasticly boosts the smoothness and fps on slow compters.

What all this means

This means that you will be able to play minecraft twice as smooth than your standard texture. So if you run reder distance small you will be able to put it up to normal no problem, that mean you will see the sun what in my opinion is a big bonus.