-Fran- :
I've had my new laptop turned off for this very reason. I don't want Win10 to push any updates, to *anything* until I'm 100% sure there are no stupid side-effects that need working on.
For all you people without a (real) choice, I pity you and wish you the best of luck.
For BIOS upgrades, luckily we're not at the point where they are also mandatory and our of our control.
This particular problem is from a BIOS update, not from Windows 10.
In regards to the software, most desktop users won't see any significant degradation of performance. The ones who might see more of a performance impact is the server people - specifically the ones who have heavy I/O workloads along with heavy network I/O. I imagine the ones who run heavily-used game servers, over-subscribed virtual hosts, big OLTP db svrs, and other similar workloads might be able to see more of an impact.