Is my CF card getting old?

I feel I can get less shots per minute on my CF card, compared to the time it was brand new. also, occaisionally but not always, it stops recording video exactly after 3 seconds. I always format it when I put it back in the camera.

Is it possible the card is getting old?

What brand is your card and how many GB?
CF cards should hold at least 100.000 cycles (or even more), but of course some card can be faulty of different reasons.
Do you own several card and is it only one card which have problems?
If you put the card with the issue into a card reader, can you access the card from your pc?

The card is Kingston elite pro 133X. It is the only card with the problem. I have no problem copying the files to my PC.

There are some reports on the net about faulty Kingston cf-card. Some returned them and got the card replaced by Kingston. Don´t know how old your card is, but maybe you should talk take it back to the place you bought it and ask if it could be replaced.
There is also some advise about first to reformat the card on a pc (don´t use any quick format!). Then put it back in the camera and then try to format it once more and see if it will help

Had the same thing happen with PNY 16gb card this afternoon. It shut down after 3 second of stooting but I'm really not to concerned about it.

Mine does the same thing on my T2i, it would fill the buffer really quick at 3 seconds, then I'd start again and it works fine. It didn't seem to do it with specific cards, but just randomly. My Mark 2 has never done it.

I formatted the card a instructed above, but the problems continue. I use 5D mark 2. Is there a benchmarking software for CF cards?

What kind of manufacture warranty does your cf card have? Might just be able get a replacement.

We had the exact same cards (Kingston elite pro 133X) and could never get them to work - also a 3 sec recording time for video. I put them down to dud cards, and after the last hardware upgrade for our 7D, they worked fine!
Hope this helps,
Cheers,
Susan.

I installed all 5d2 firmwares. After 3 years of saving tens of thousands of photos, I doubt I can get anything from Kingston.

Susan, will you buy my card at a good price?