I've been using VAC for quite a while with my Flex-3000.

This is the one I currently use. It's not free, but inexpensive.
A bit cranky to configure.

http://software.muzychenko.net/eng/vac.htm

Looking at switching to this software, it's more elegant, and easier interface.
Technically free, but please send 'em money. A different pay model.
http://www.vb-audio.com/Cable/index.htm

If you fiddle around with various audio sources like I do for music and multiple radios,
Virtual Audio Cables are cool. They are also, by their nature, quiet as far as PC noise.

I run Windows 10 64bit Pro. Because I run a Flex-3000.

FL-Digi is my main software for digital modes and logging.

MultiPSK is my secondary digital software. More modes.
Crazy ugly interface. But kind of fun, for Utility DXing.

http://www.udxf.nl

I tend to tinker around and tear stuff apart, then screw it up.
Then fix it. Because, I can. I'm a bit of an SDR enthusiast.