External PCIe 3.0 enclosure for video cards?

[magellan]

I've heard of custom external PCIe 3.0 enclosures for laptop video cards. Do these enclosures cause any performance issues (e.g. FPS loss, stuttering etc.)?
Do the laptop ones use thunderbolt connections/interface?

I'd love to get my video card away from me and the rest of my computer. I wouldn't mind locating it right next to my window or wall A/C unit.