What difference will a better M.2 make to load times?

I'm waiting for a new system to arrive and the OS is installed on an Intel p600 M.2 drive.

I'm concious that these aren't great in terms of speeds (Read 1570MB/s Write 540MB/s) and I'm wondering whether I should have splashed out on a Samsung (Read 3100MB/s Write 1400MB/s ).

What real world difference would I notice in boot and load times, and will it be an easy task to swap Windows over to a Sumsung M.2 if I order one?

Unless you have a stop watch, I would say very little difference.

Windows startup is limited by lots of little files, so any SSD makes a huge difference, but actual transfer rate has little impact.

With games, often they are limited by processing / how the games loading routine is threaded, rather than being limited by sequential read speeds.

As above doubt you'll notice it vs. SSD but the biggest gains will be tidying up the bios to stop boot seeking HDDs/DVDs etc. I'm HDD free and its pretty fast but a mix of the Samsung M.2 and 4 SSDs.

I did this a few months back with nvme 950's on two systems, the change was easily noticeable on my 5930k system (Im talking 2 second bootup), but not quite the mech to ssd jump.
On my 6700k it barely made a difference.

That's really helpful. Thanks a lot. My system's based off a 6700k so I'm not going to fret anymore.

How fast do ya need it to boot? I'm on an old Samsung ssd and it only takes 8 seconds, by the time I have sat down and turned on my monitor it's ready to go. If you do get one of them super fast ones let us know how fast your boot time is, you've got me interested now.

This is one of those rare moments in my life where I'm getting something almost without compromise. I want to make the most of the opportunity, and although there's little real world difference between 8 seconds and 12, it's something I think would give me irrational satisfaction every time I switch on!

That said, the hassle of transferring the OS over is a higher price to me than the difference in m.2 drive costs, so if it's sub 10 seconds, I'll be very happy.

I think my bios doing stuff is slower than my actual boot time with an ssd.