[moonbug]

Well, the K520 is a single AIB with two discrete GPUs on it, each being a GK104 with 4GB (which seems to match the spec of the K5000). A g2.2x instance has a single GPU - ie half a K520 - assigned to it.

Your claim surprised me enough to stand an instance up and take a look for myself. Sure enough, they report having 4 K520 devices.

[Sanddancer]

Gotcha. I was looking at the spec sheets of the various instances, and could only find that they are GK104s. I didn't think to look to see if there was a dual GK104 board, because video card makers tend to do that only for their high end boards. Definitely makes sense, though, for the density Amazon would want to run in.