d0c5i5, ideas appreciated. Unfortunately I need two screens tied to the same OS/instance. I agree this stuff can be frustrating, but the light at the end of the tunnel looks incredible, as we all can imagine. Unfortunately it seems I spoke too soon. After reverting back to a single monitor passthrough I'm experiencing intermittent audio issues. It's related to mouse activity over the USB passthrough (sounds like a robot in an echo chamber). Either my settings changed, or I didn't run enough initial testing.
ciuly, good question. I'm limited to HDMI because the screens are 40 feet from the PC, hence one HDMI port per card. Honestly I hadn't considered the dual-output DVI option these cards have, although I'd like to avoid an active DVI extender due to my current investment in HDMI cabling. Maybe I could try a dual-port HDMI card, like the R7 240.
It seems accepted that this is still very experimental, which is understandable. Do many of these issues disappear when using a server-grade mainboard, or do the complications reside elsewhere?