critical

Dear Mojang AB, I recently upgraded from Windows 7 to Windows 8. It does not work well with my minecraft. I got Windows 7 on a flat world 100 fps, but with the modded drivers hopper.minecraft.net I get all the time 10 fps. I do fullscreen than 3 to 5. Why is this so? And how can I fix this? (the reason I modded drivers using hopper.monecraft.net is: I can not otherwise play 1.7.4 and higher) Sincerely, Jaap Rodenburg (jumping_monkey21)