Two things:
Win10's disk access is slower than Win7's, so that's nothing you or we can do anything about. As for the Printer Drivers, they are usually completely different from one OS to the next, so it's very difficult to compare their performance.

However, in both cases, the new OS shouldn't be 3 times as slow, as your numbers seem to indicate.

I would take a look at external applications that may have an impact on Workflow's processing, in particular the anti-virus that's running on the new system. It may be more aggressive than what you had on the previous OS. You should be able to whitelist Workflow's working folders so that the antivirus doesn't look at each temp file being written to/read by the system.

You might also want to check if any extra software is running on that server, compared to the old one, which could use up more memory and therefore force Workflow to swap to disk more often.

Let us know if you find anything.
Technical Product Manager
I don't want to achieve immortality through my work; I want to achieve immortality through not dying - Woody Allen