Last year they did not start reviewing applications until the deadline (at least not openly). The first interview invite reported was within 2 weeks of the deadline if I recall correctly. Stanford trickles them out in general, but it seemed there were a couple spurts (one around Christmas).
This year, things are a bit different. They moved the notification deadline for Round 1 ahead of Christmas. While they also moved the application deadline up, I think this shortened their time to review applications .... so the trickle may be less, but I would plan on it being more trickel than spurts. Its annoying and agonizing, but its the process. A lot Round 1 admits from last fall had interview invites at Christmas and later ... so I wouldn't get too bent around the timing issue of the invites.