My mobile phone is slowed down after installing the new update lolipop

2 weeks ago, I reset my HTC phone to factory settings.

lolipop update required to be installed then I downloaded it (850 mb) now my phone is so slow that when I play games it takes time to launch the game and the response in the games is so bad. Also I face that problem of slowness when I type on the keyboard. I installed antivirus and memory booster this boosted the speed a little bit about 25% but still I face the problem, I'd be grateful if you respond :)