Crackling static noise when running sweeps

[Bruce N]

When I run a test sweep in REW using FlexAsio I get a crackling static sound from the test speaker. Any ideas what may be causing this?

I have tried many different settings in the FlexASIO configuration file with no change.

ASIO4All doesn't seems to recognize the nvidia video card in this Dell PC running Win10. I have updated the video drivers.

Thanks!