Lately I've started running the Windows 7 Beta for some development experiments, using VMWare's fantastic dual-screen support. As I've written before, the general experience is great, even under virtualization with 1GB of RAM, and having it wall-to-wall on multiple displays makes the illusion more convincing.
An interesting thing I've noticed is that my old habit, when I want to stop working in a VM and free up the resources, is to suspend the VM. This action is roughly (but not exactly, depending on the VM you're using) equivalent to "hibernating" a laptop (S4 power state) -- memory is mapped out to a file and the device is powered off.
I usually do this because this hibernate/wake is faster than a shutdown/boot-up, not because I'm trying to save my actual work state (open apps, etc.) Especially with Windows server, but even with XP and Linux, this approach is the faster way to hop in and out of a work session. On the laptop, it's a way to save the battery power involved in a longish hard boot.
In Windows 7, VM suspend/resume (==hibernate/wake) seems to be slower than shutdown/boot. That is, even with no user apps running (which could take up an arbitrary amount of memory and thus lengthen the map-out / map-in time), boot seems faster. I say "seems" because I have only 2 machines to play with, and they are not clean images just for this test, so I won't pretend they represent absolute objective truth.
What does this mean?
It would appear that the boot process has been cleverly streamlined so that a cold machine gets to a running, usable state before all of the additional services and apps have fully loaded and gotten running, and that this is orchestrated using knowledge that a white-box VM player doesn't have.
Some folks may point out that having to reboot an OS is itself questionable ... and indeed the boot is optional -- I only reboot my XP desktop every couple of months when some security patch or other requires a restart.
But in the world of laptops and netbooks, things are different: every minute of juice is valuable, so there's always the consideration of the cost of a hibernate/wake vs. sleep vs. leaving it on with the LCD off. And that equation has just gotten a little more interesting: for Win 7 on a laptop, if you're not going to be using the machine for a while, it may turn out to be faster and use less power to do a shutdown, and just reboot later.
While this may seem like a fairly inconsequential gimmick about boot times, it is a step in the right direction as we look at the huge array of gadgets we all use and which eat a ton of phantom power. The Windows PC is kind of the holy grail for a fully-off / instant-on experience, and Win 7 appears to take a measurable step in that direction.