In this paper we discuss certain aspects of residual stress measurements using energy-dispersive synchrotron X-ray diffraction using very high X-ray energies in the range up to 200keV. In particular, we focus on the strain resolution and its relation to the geometric contribution to the instrumental resolution. This energy range together with the brilliance of insertion devices allows measurements in bulk materials with penetration approaching those of neutrons, and the technique is demonstrated to have a high potential for residual stress determination. However, the use of high X-ray energies implies a relatively small diffraction angle and in turn a relatively elongated gauge volume, which favours the application of the technique to essentially 2D problems.