Blender has stopped working

Windows 10 latest build
GTX 970 4GB Latest drivers
intel 4790K

Blender 2.79 using GPU compute and GTX970 selected in Sys pref.

I’m having an issue where Blender 2.79 repeatedly stops working and needs to close.

It is happening consistently when making simple adjustments to the Principled BSDF shader in ‘rendered view’

For example, this morning I had a very simple studio HDR environment loaded, then I added an image texture to the base color of a simple sphere mesh, adjusted the metallic slider and BOOM ‘Blender has stopped working and needs to close’. Opened up a new file, repeated the process and once again Windows reported it needed to close.

Any ideas?!