The internal force of a variable displacement vane pump has been studied in detail with ten Computational Fluid Dynamics (CFD) cases with different pump speed and eccentricity. The internal moment increases considerably with faster pump speed, and at higher speeds, it can exceed the moment due to the spring force causing the slide to regulate at much lower pump discharge pressure. At low pump speeds, the effect of eccentricity is minimal. The maximum value of internal moment is expected to occur at high speeds and maximum eccentricity. There are two reasons for variation of internal moment with pump speed and eccentricity: (a) the variation of effective pressurized area of the slide changes with pump speed and (b) higher pressure in the blind ports at higher eccentricity. This study provides insight into pump forces during high-speed operation of vane pumps.