It is faster, but actually not that much. In your case, it's difficult to tell without knowing more about the specific scene. Spherical collision detection isn't a swept approach, i.e. it's possible to "jump over" obstacles if the translation is quite long compared to the collision objects. If , for example, you translate by 5,0,0 and at 2.5,0,0 there's a sphere of radius 1, this won't be detected. Might that cause the problem? Anyway, if it isn't a huge performance problem, i would stay with what works for you. Ellipsoid collision detection is simply more powerful, sliding is better etc. So prefer it if possible even if it's a tad slower.