[teamonkey]

Each game frame is a snapshot taken with an infinitely small shutter duration but displayed for 1/30s or 1/60s (vs one movie frame, which has a shutter duration of, e.g. 1/48s and displayed for 1/24s).

So over-framing game frames will not produce motion blur, it'll simply merge two still images together. You need to simulate motion blur (usually as a post-process). This of course takes more time to render, potentially lengthening the frame times.

[dlubarov]

I don't see any theoretical difference. Provided our sampling rate is sufficiently high, merging together "snapshot" images should give exactly the same effect as motion blur.

Though in practice it would be difficult to render more than a few snapshot frames between the display's refreshes, and with a low sampling rate there would be noticeable errors, particularly if you take a screenshot of a fast-moving object.