Pan/scroll is fluid, but whenever you drag off a node to wire it to an existing node or new node, the wire lags behind the cursor. - YouTube is an example. This happens in a new empty project in both 4.6.1 and 4.7.0 preview 8, on a Late-2014 5K iMac (with M295X).
Dont have this issue on osx 10.10.2
I’m also using 10.10.2.
It appears that the problem only happens when SmoothMouse (http://smoothmouse.com) is enabled.
This is an external application which we do not have integrated compatibility and could cause issues like the one you are experiencing. I would definitely suggest disabling this external program while in the editor.