I was shooting some action shots this past weekend on CH mode. I was using the MB-D10 with an EN-EL3 with a good charge with a Sandisk Extreme III 8gb card. I noticed during some of the sequences (couldn't tell you how many continuous shots) the speed of the camera slowed considerably.
I was on Shutter Priority @ 1/2000. Was I overloading the buffer? Battery not strong enough to keep up?
#1. "RE: CH mode slow down" In response to Reply # 0
The shutter rate slows when the buffer is full is writing files to the card. The fater the card the longer you get before the rate starts to slow. The buffer read/write speed is higher than the card you are using and the bottle neck is the card wirte speed. I was shooting motor sport (A1 GP) this weekend with a Extreme IV and at times with a rate of 7 frames/sec. The camera would start to slow after about 3 seconds of a continues burst.
#2. "RE: CH mode slow down" In response to Reply # 0
Definetly sounds like a full buffer. The Sandisk Extreme Ducati, or new Extreme IV cards have a write speed of 45MB/sec. and will allow the D700 to capture many more images in the same amount of time, when compared to the Extreme III cards. You can tell the difference. Good Luck and Enjoy your Nikons!