I am using a 60D, and have a 16gb Sandisk Extreme Pro 95mb/sec card. I am able to get 3x on 1080p24fps about 75% of the time unless there is alot of action happening on screen and the iso is low.
If it is really busy, higher iso value, then setting it to 2.6 keeps the buffer from stopping.
With HDR mode, I shoot 720p@60fps, and keep the bitrate at 2.4 and it still goes.
FYI, with all these settings, I have audio disabled.
I also have a 8gb 45MB/sec extreme card from sandisk, and they pretty much give the exact same results as the 95MB card... go figure...
