In this paper we present some results of investigation into the performance of a technological CO2 laser experimental model developed on the basis of an original combined technique of a volume discharge formation. The active volume of the discharge zone, gas flow velocity through the discharge gap and discharge length along the optical axis in our experiments were 1000 cm3, 50 m/s and 80 cm, respectively. We have studied the laser operation in different pumping modes and different pressure of helium-free and hydrogen containing gas mixtures. Long-term operation of a laser without change of the gas mixture containing CO was investigated, as well. It was shown that high lasing efficiency (up to 22% and up to 28% if the contribution from the cathode drop is reduced) and specific output power of several units of W/cm3 could be achieved in such laser systems.