|There is a difference in the thickness of the sheets though. there is 1/4" and 3/8" sheets that are designed to go OVER other plaster or drywall. Then there is 1/2" drywall, which is used as new walls most of the time and is the most popular. 5/8" drywall is a firecode brand and is used in kitchens and garages that are attached to the house.
The only other difference is the length and width. sheets come in 40" to 56" wide, but mostly 48" wide. Length is 8' - 10' - 12' - 14' - 16' long and should be sized to fit each particular wall or ceiling it's going on.