I felt choppy when i scroll up-down in Gmail. There are two workarounds for this issue.
First thing, change your theme from Clearlooks. But, I really like clearlooks theme.
The Other one is, play with xorg.conf
Edit /etc/X11/xorg.conf
Find this Section:
Section "Device" Identifier "Configured Video Device" EndSection
Add some properties & change it to:
Section "Device" Identifier "Configured Video Device" Driver "intel" Option "AccelMethod" "exa" Option "ExaNoComposite" "true" Option "MigrationHeuristic" "greedy" EndSection
This workaround worked with Intel Graphics Card Users. For non Intel Graphics Card Users trying the above is experimental.
Do Logout & Login. This should solve the choppy scrolling issue in Gmail.