The GTX 970 lacks support for HDCP 2.2 (copy-protection standard), which will be used on the UHD Blu-Rays, so no (from nVidia, only the GTX 960 supports HDCP 2.2, IIRC). Playing "ripped" files, I don't see why not - my laptop (i7-4600U with IGP) can do that - it's not exactly demanding.