Hi Rodney,
It can be advantageous to put all your 'Windows System', Program Files, etc. onto a C\: drive (on an SSD, or even - motherboard dependent - one of the 'M2' drives). Then, you can move your 'My Documents', etc. onto a second SSD drive (watch the drive size - put all your data on one drive means an exponential feeling of sadness when it all packs up. You can then use a third drive (your HDD in this case) to archive data from your My Documents drive.
Onviously, you still then need some form of totally reliable backup strategy to duplicate your data further - preferably off-site. I personally backup to five locations. I have two 1TB SSD drives (E\: and F\
internal to the machine taking backups from the C\: and D\: drives. I then have three dual-2TB NAS drives, configured in RAID1, also taking the same backups as the E\: and F\: drives. One is in the garage, one is in the observatory and the third is in a fire-proof box under the stairs. I have a fourth NAS ready to be pressed into service as soon as, or if I ever, get a decent broadband connection.
All of my data transfer speeds are just as fast as they can be, and not one single bit of data is 'in the cloud' and thus not freely available to whichever national spying service wants to try and decipher my Dark Frame images
As far as PixInsight itself is concerned, I have this installed on both the observatory (reasonable-spec) PC as well as the (ultra-high-spec) PC that I use as a daily number-cruncher. I also have TeamViewer installed on all of my machines so that I can perform all the remote comtrol that I am ever likely to need.