"Ah ok, that's what people meant by "one eye mirroring." Thanks. Just making sure I pick the right components.
Edit: but wait, and this is so noob but we're already down the rabbit hole- from what port do people typically run their main monitor if most cards have one HDMI out? Isn't that for the Vive itself? Or I guess just DVI."
Depends on the card. My 1080 only has 1 HDMI, 1 DVI, and the rest are displayport. However, an update at some point last year made my Vive not work well when my second monitor was connected to the DVI port and I had to use an HDMI to Displayport adapter. Valve support said Vive is finnicky with monitors using a DVI port.
Short answer: Use HDMI or Displayport (use HDMI to Displayport adapters if necessary) for your monitor(s).
Define "working well" for me here. I have a second monitor hooked up with DVI (it's an old monitor and doesn't have HDMI) and I'm curious if it's affecting my Vive experience.