I feel a bit stupid asking for help here but I can't seem to figure out what's going on with my SB-900 firing remotely.
I'll have my D700 in Commander Mode and the SB-900 in the Remote setting on a stand a few feet away firing rapidly at first. But then it begins to slow down dramatically, taking longer and longer to recycle/recharge. Yes, I've changed batteries but this isn't the source of the slowdown. I've even attached a battery pack with 8 fresh batteries and still experience long recycles (as in 15-30 seconds) between shots once the slowdown begins. When it does recharge I get to fire off only two shots, and only two shots, before it pauses again.
This only occurs when I'm shooting remotely. When the SB-900 is on-camera in the hot shoe I can shoot all day long rapidly--or at least until the flash unit goes in thermal overheat mode.
I can't figure out if this related to some weird battery drain in remote, or maybe the camera card getting full and slowing things down. Very annoying.