A fast nonlogarithmic magnetization relaxation has been observed in Bi2Sr2Ca1Cu2Ox single crystals for the initial time interval. This relaxation is attributed to a viscous flow of Abrikosov vortices for currents axceeding the critical value. This relaxation gives way to a logarithmic relaxation upon the transition to thermally activated flux creep. The field dependence of the logarithmic relaxation rate has been studied. The magnetic moment sharp change for the H perpendicular-to c direction has been observed. This effect is probably due to collective vortex pinning.