slightly tangential:
I was planning this Win'10 CAD-tower around an SSD C: and an HDD E:.
After doing some research, I learned my Win'10 x64 CAD programs all preferred to live on C:, as a lot of 'legacy' scripts & plug-ins would not play nice otherwise. Allowing for upgrades, bloat, suite libraries etc etc, the necessary SSD capacity was not affordable.
So, reluctantly, I reverted to 'Plan B', which was a trio of WD 'Black' terabyte drives for C:, E: & F:, the latter pair set to 'spin down'. My sprawling 3D model library & file archive live on E:, backed up to F: and external drive(s).
As regards migrating a Win'7 x32 system: I would be very, very reluctant to put Win'10 x64 on that old drive.
First, it has 'mileage'. Some years ago, I lost both a bespoke CAD-tower and a Browser_PC to a cascade of drive failures. Still rankles...
Second, clean-install or not, I'd rather put new OS on a new drive, move the old drive to eg E: but now set to 'spin down'.
YMMV but, for my work-flow, a couple of seconds saved at boot or load time seemed a poor trade for an additional terabyte drive. FWIW, I spent some of the savings on maxing-out mobo to 32 GB RAM and upping CPU from 3x2 to 4x2 cores...