I don't have an exact time, but I can tell you the HD version of the Air is no speed demon on boot times(slower than my year old MacBook for sure, and that took ~30-40 secs). If you are looking for a speed demon the Air isn't for you - but to me the respectable(if not blazing fast) speed is well worth it for the portability. Outside of the boot time, I haven't noticed any speed problems. Most of the time my Air is in sleep mode, so it is up to speed within seconds of opening it.