Hi Malcolm,
Refresh rates are @ 60 in the monitors Dat, I have 2 P5000's in a SLI Mosaic 2x4 for external display and a P600 for local 1920 x 1080 display. Total external monitor resolution is 15360X4320

. I know this is a large canvas....I use a .bat file with gpu affinity to launch TD.
I have 2 970 Pro's NVME drives in Raid 0 for the media drive and it tests in crystal disk 7gb a sec sequential read. I also use Geometry for some effects with little to no overhead and same results...30 fps. unless I turn off real time....
Been testing and a few notes....not sure if they are 100% related
1) when I play hapQ video file at full resolution 15360X4320 and the disk read rate in the moviefilein top exceeds 12,000 mbs the Frame Rate collapses. 2fps is typical if this happens. Performance Monitor says that the moviefile in top is waiting on the hdd. 12000mbs is only about 1.5 GB a sec. My Drives support about 7 gig a sec. Mabe PCI lane saturation? not sure of the issue or if it is related to the 30 fps talked about above. I have tested on many different servers with same results. the same 12,000 mbs wall.
Asus and Gigabyte motherboards with x299 chipsets were tested. NVME drives are in 3.0 4x pci lanes.
Motherboards with the x370 chipset seem t0 only get half thy bandwidth they choke @ 6,000mbs
If I split the video into two files ( each well below the 12,000mbs) no problems and will play a 30 fps video fine at 30 fps. But no matter what i can't seem to get 60 with v sync on, with it off screen tears.
FYI I am on Windows 7 and latest Nvidia drivers.