I have an i7-7700 (not k) running Windows 10 and a GTX970 CUDA in an ITX case.
I just upgraded to HQ Player 4 Desktop.
I can run 44.1/48k source material through Roon with 2 band DSP and convolving a room correction wav file in HQP at 256 DSD (x44.1) using ASDM7EC and ext2.
With 96 kHz source material I get stuttering, but can run ASDM5EC without stuttering. Four cores are running between 25 and 60%.
CUDA is greyed in HQP4 but isn’t being used by the program. It probably thinks there is no performance advantage.
Edit: I’ve got CUDA working properly now and can do 192 kHz to DSD 256 with ASDM7EC and ext2; see here