Motion artifacts

Recently, I am getting motion artifacts when shooting video of fast moving objects with my 5D2.
Here is a sample:

https://drive.google.com/file/d/0B5O1W4-s1SUbcXBfaVItMm9uRk0/view?usp=sharing

Is it my camera? my card? my PC? or else?

The problem is intermittent. I did not try different cards yet.

How do I avoid the problem in the future?

Looks like card issues.Was it this specific frame only that got corrupted?

No, it was a sequence of frames with varying degrees of the problem.

I had this with my very first HD Camcorder and had the same with my old DV Camcorder. It's not the card, it's the technic. Maybe anything with sensor :(

Looks like card issues to me too. Seen those blocks before, and it was a card dying. Changed card, issues went away. Doesn't help the footage though. Damn, that sucks (the artifacts, not the footage, which looks awesome)

Yep.Card.Do you usually format the card in camera?Just curious.

I always format the card in the camera.

I am surprised to report that I am not the only producer of artifacts.
See this clip in the last second:

and this clip on the 23rd second:


These glitches do not exist in the original video.
Check your own clips, guys!

@wideweb: Now have you changed the card and the artifacts are gone? Let us know, please!

I have notices lately that the preview here at P5 has changed and when the clips finishes the preview it stops in a gray view with big blocks and artifacts. Another change not fully tested. Is it possible it has something to do with that?