You can use modded intel nvme drivers in your 600p drive, look for >64bit Intel NVMe Driver v18.104.22.1687 mod+signed by me< here
As for the boot time, I have no experience with that chipset, but I can share you mine with Z68, Z77 and X99. I moved from a Z77 board to an X99 one some years ago and noticed that it took way more to boot, but never really cared. Besides that, I also replaced a crucial M500 with a 850 EVO. I purchased an nmve drive a month ago and windows load times are better, but the windows animation still takes a bit. Note that this is a Windows 7 system.
The 850 Evo ended up on an old Z68 rig I have, which was already blazing fast to boot with a very old M4, but now it's even faster.
I can't explain the reason why the X99 system is slower to load Windows 7 (at least during the boot animation), but I can only guess:
· X99 systems (and perhaps others like Z270) boot using a lower performing cpu state.
· A driver (motherboard related, most likely) is slow to load. This could be audited with a tool that I can't remember (this one might work
's comment, I wouldn't use those words. Instead, I'll say that the benefits can hardly be noticed by users or are even hard to measure for tasks like game loading time, application start up or things like that.
One more thing: I really don't think that heat is going to impact boot times (or that you should worry about it right now, buy a cheap heatsink later down the road if you want), nor will the use of an specific nvme driver.