Have done this on every build we have done since 1993. Back then we used a boot loader which hid the OS partitions from one another. This was very valuable even on home setups where kids use the machine. The boot loaded existed on its own mini partition. If you turned on the machine, you would have to enter a password to get on the "Mommy / Daddy" boot ... if you didn't within the set time limit, it booted to a different partition that had all the kiddie games on it ... and no matter what they did, they couldn't damage anything that was on mommy / daddy partition.
But you don't even need additional drives to do that... all could be done on 1 HD with partitions
Here's a suggested alternative
1. SSD with Win 10 on it
2. SSHD partitioned as follows:
C:\ 128 GB for OS
D:\ 64 GB for Page and Temp Files
E:\ Programs
F:\ Data
3. The way I do it is:
a) I connect the SSHD to 2nd lowest numbered SATA port and install Windows to new 128 GB partition. Ethernet cable not connected.
b) Turn off WU's ability to install hardware drivers
c) Install all hardware drivers from media or manufacturers web site
d) Run WU how many times it takes to finish
e) Create other partitions. Change all the drive letters to something else (say X:\) and then back again ... this will stop OS from loading in default order which will change when you add SSD. Label all the Partitons .. for example
C-Boot
D-Page-Temp
E-Programs
F-Data
f) Move temp and page files to D:\
g) Install programs to E:\
h) Copy data files to F:\
4. Then, shut down and disconnect SAT data cable\from SSHD and connect Data cable to SSD on lowest numbered SATA port
5. Repeat steps b, c, d and f
6. Repeat g making sure to install the programs in same folders as before ... this will set up all registry entries
7. Shut down and reconnect data cable to SSD.
8. Boot to BIOS and check boot order.... should be SSD 1st, SSHD 2nd ... if not, fix it.
9. Boot from SSD and open Disk Manager. Change the 1st partition (128 GB W/ Windows on it) to X:\. Label it something like X-SSHDBoot
10. Change the others to same letters as before ... if they are the same already, change to something else and then back again. Move the page and temp files to D:\ as before
Now you can simply boot to either OS by selecting the proper drive in BIOS.
- Programs are installed once using same space for both boots
- Page and temp files use same space for both boots
- All data accessible from either boot.
We do this even when only 1 OS involved where the OS on the SSHD is just a dupe of what is on the SSD. I case the SSD goes south, everything is still accessible w/ no downtime
Again, been doing this since 1993 on 100s of builds and never had a hint of an issue
Why you don't want to install Windows with both drives connected ? SSD dies, MBR gets fudged or anything else and you screwed.... the menu you need is not accessible. No fun being outta business or having no access to your stuff while the warranty process takes weeks to finish.