High-precision tracking and charge selection with silicon strip detectors for relativistic ions has been investigated using a 12C beam of 1.5 GeV/u at GSI with prototype modules developed for the AMS tracker. The ionization energy loss is measured and compared to the Landau-Vavilov theory for ions of charge number up to Z=6. The linearity in Z2 is examined. The capability to distinguish different Z values based on the ionization energy loss is evaluated. The spatial resolution of the silicon strip detectors is investigated for carbon ions. The angular distribution of multiple Coulomb scattering is studied with lead absorbers. The results are compared to the Molière theory and the Gaussian approximation of GEANT calculations.