Speed was an issue on Windows 7 (PSv2), but they sped it up considerably in Windows 8 (PSv4, I think). Maybe installing the current PowerShell version helps; I doubt it's inherent in the OS.
I'm on Windows 10 and I agree it has improved a lot since Win7, but it's still not pleasant. I'm rocking a 7200rpm spinning disk, so as suggested by adiabatty, getting an SSD might help.
