Many CS6 users who are installing El Capitan on their Macs are finding slow-downs and other problems.
CS6 is almost four years old. Adobe has been saying for several years that no updates will be available for CS6. CS6 is not supported for El Capitan. Basically, you're on your own.
One thing you can do is to turn off Auto-show Menus (System Preferences > General) which causes crashes for most people.
It's right there on the top. Second line after Appearance and it's already off.