Yeah I did that too. I disabled all pre installed apps that I don't want to and unchecked the "Show notification" checkbox, including Google Chrome. That browser **bleep**, it runs so very slow. Firefox and Opera are the best.
Just I didn't know if that way could boost the phone up and made it run a bit smooth and faster. But yeah it works.
@ Meid, you don't have to reset the phone. All you have to do is, after upgrade the phone to 4.3, and do the factory data reset. Disable it and then just reboot the phone.
- Uncheck the Show Notification checkbox
- Clear cache
- Clear data
- Disable
Hope it helps.