The significant battery drain during sleep is definitely a problem that I am inflicted with. Others have reported it as well and it is also going on with the Surface Book. There is a long thread on Reddit on it. I resorted to changing the settings to go directly into hibernation until it gets fixed. Sleep studies I have run show it to be something related to the Intel Integrated Graphics.
I have also experienced random slow boot times where it gets stuck on the surface screen. It doesn't happen all of the time though. Obviously, there are a handful of bugs going on that are affecting some, but not all units (which is a little baffling).
What Nutmegz said above. Try removing the type cover when you boot the SP4. If I boot mine with the type cover on and folded back it takes 2-3, and sometimes 4 minute to boot. Without the type cover attached it boots normally. Usually with the type cover attached and the SP4 in laptop position, it'll boot fine, but not always.
Good question, no - I'm not using UEFI secure boot. That's new to me, I had to look it up .
Regarding virus scan, so far I've just left it with Windows Defender. I'm not loading any more software on it until these issues are resolved (or I decide to return the unit, which is a possibility at this point).
Sorry to resurrect this but I have an update. I'm surprised that more people aren't complaining about this issue. I'm now on my 3rd SP4 and the issue continues - but has improved so the delay is only now about 30 seconds. In any case, I was informed via a Microsoft forum that there is a known bug where the unit takes a long time to boot up if the keyboard is folded behind the unit (which is how I normally boot).
Isn't everyone impacted by this? Like I said - it's happened on all three units. I have an I5 128.
By the way, the previous two units were plagued by issues. This one seems to work well, except for the boot time issue. One MS rep confessed that the early units had lots of problems.
FWIW, it's not just the type cover. I've had the very-long-boot happen with a Tascam US-144 USB audio interface plugged in. I presume there is something about enumerating some USB devices at boot time that causes the issue.