We report the performance of a laser based on a 9.8% doped ceramic Yb 3+ :YAG operating in quasi-Continuous Wave (QCW) and in Continuous Wave (CW) at room temperature. The maximum output power of 9 W with a slope efficiency of 73% at 1030 nm was achieved in QCW. We investigated the problems originated from thermo-mechanical properties of the ceramic and we studied their effects on the laser per-formance finding that either the slope efficiency or the laser threshold are thermal-losses independent. Finally, we report a characterization of a low losses tunable cavity for several laser wavelengths.