2.6 quad core pc on xp reaper 3.7 pre goes up by 30% on an average project. I do have 4 monitors though and i have not looked at how much it does on similar programs. Maybe it's normal for scrolling?
Preferences-Editing Behavior-Mouse Modifiers-Context: Arrange view-Shift+middle drag= hand scroll. That's default for me, (never changed it before, so I guess that's default.). Hope that hits the spot.