Crash

well, i crashed 4 times in a row trying to play CF.
when i play i get constant FPS lagg, even though I get 98 FPS Avg.
and i got max 60 ping.
I got gamebooster on.
cleaned my computer with advanced system care.
why am i lagging?
my computer stats are good.
and also when i back space it's very slow.
solutions?