A diode-pumped Q-switched ${\mathrm{Tm}}^{3+}$ -doped double-clad silica fiber laser is reported providing average powers of up to $30\mathrm{W}$ at pulse widths of only $41\mathrm{ns}$ and repetition rates in the range of $10–125\mathrm{kHz}$ . Up to $270\mu \mathrm{J}$ pulse energy was produced. Amplified spontaneous emission (ASE) buildup limits the maximum peak power, and the pump power and average output power at the point of ASE induced clamping were found to depend linearly on the repetition rate.