There seems to be some confusion as to the sync speed of our remotes and lights. I hope this will clarify...
"Sync speed" refers to the maximum shutter speed at which your camera can capture an entire frame that is exposed by a flash. In today's cameras, this is typically about 1/160 to 1/250 of a second. Cameras trigger a flash as soon as the first curtain opens (rear sync works slightly different, but will have the same effect). At your sync speed (x-sync) and below, the rear curtain is still out of the way, and not blocking your image sensor (or film). At speeds above your x-sync, by the time the first curtain opens, the second curtain has already started its travel across the frame, blocking a portion and resulting in a black bar, typically running horizontally, either at the top or bottom of the frame. The more you exceed the x-sync, the bigger the black bar gets.
When using a radio remote, like CyberSync, Pocket Wizard, Cactus, etc., there is an inherent delay. This delay varies from one manufacturer to another. Sometimes, the delay exceeds a camera's x-sync, causing black bands, despite the camera's ability to operate at that speed. Example: an inexpensive remote will have a delay to where the remote's sync speed is 1/60, but your camera will sync at 1/250. To avoid the black bars, you will need to shoot at 1/60.
We advertise the CyberSync to sync at 1/2500 of a second. This means you can sync at your camera's maximum sync speed up to 1/2500 of a second. If your camera's x-sync is 1/160, you can shoot 1/160 or slower. This does not mean you can automatically shoot 1/2500 on any camera with CyberSync, as the x-sync is a physical limitation of your camera.
Some cameras, particularly point-and-shoots with a hotshoe, and some (older) Nikon DSLRs, use an electronic shutter (the DSLRs use a hybrid shutter) that effectively start sensing/stop sensing, rather than using a moving shutter. This allows the entire frame to to be "exposed" simultaneously, thus achieving higher sync speeds. We tested (on a Nikon D40) and found our CyberSync to not be the limiting factor up to 1/2500 of a second, when the camera has that high of a sync speed. Some well-regarded remotes publish a sync speed of about 1/500 of a second, making ours five times faster.
Sync Speed vs. High Speed Sync vs. Hyper Sync will be discussed in a separate thread.