Start Photoshop with Plugins disabled by holding down the Shift key as you start Photoshop. That way we can see if a third party is causing the problem.
Uncheck Enable Flick Panning in Preferences > Tools
Go onto Preferences > Performance > Use Graphics Processor > click on "Advanced Settings" and set from Drawing Mode from Advanced to Basic.
Let me know how that works.
Thanks for the reply gener. Have adjusted my setting per your suggestions. Still no dice. Rulers on causing inexcusable interface delay.
If your system uses dual GPUs, you must make sure it is using the High performance card, and not the slower Energy saving card.
Also look at the other setting suggestions here.
If that does not work, try resetting Preferences as shown below.