High pressure rocking cells have overtaken the use of stirred autoclaves as the standard industry method for the first stage laboratory screening of kinetic hydrate inhibitors (KHIs). This study investigates the effect on KHI performance by varying different parameters in the rocking cells. This includes the rocking rate, rocking angle, gas−water ratio (GOR), glass versus steel balls, cooling rate in constant cooling experiments, and KHI concentration. A gas composition containing C1−4 hydrocarbons, CO 2 , and N 2 was used, which was predicted to give Structure II hydrate. Isochoric experiments using the constant cooling method or isothermal test method were used on N-vinyl lactam polymers.