I recently updated my Garmin 496 for data and when talking to the tech ( I had a tech issue to update the unit on flymygarmin.com) he advised to turn off WAAS and your unit will update pages etc much faster and that the use of WAAS on software updated units is only about a 10 ft difference. They apparently had WAAS when GPS was less accurate but now the units are so accurate that WAAS is not that musch more accurate. I have noticed a more rapid update on my unit as a result. Regards Gary