I too am getting dropped frames with h.264 1920 1080 but this was after I had pulled slx from a sequence over an hour long (that did not drop frames) down to six minutes, which still did not drop frames until I added a filter to a layer of video. Now it hiccups at transitions. I understand why H.264 is not considered an editing format having never been a fan of Mpeg in any format, but seem confused why the dropping only happens after I add the effect, and then at transitions. Obviously the render is in the same format.
Am running 7.01 on a 3.06 Intel Core 2 duo 4gb 1067 mhz ram (Imac 21″) Lacie terrabyte drive with five partions via fire wire 800. The connection passes through one drive that is not powered up.
Thanks,
Barnaby