98 I put together some mods to test 1.8 performance on my computer. I approve of it but there are other problems so...... lets stick with 1.7.10 for now.
if you want to know: in a cave 300fps. I never even had this in vanilla before
while flying generating new terrain and being close enough to the ground to have most of the "this now looks nicer stuff" about 30 fps in 1.7.10 without mods to combat lag and the mod that makes the world nicer I get constant lag spikes that bring me down to 0 fps for multiple seconds