The jet seven is a good cooling unit.I have the Aero 4 desighn on my 2.8.Now that you no the procedure to install it .I would take it back off.Clean the die and HSink re-apply Artic Silver and re-install it.Make sure the HSink is seatting flat on the die.Also make sure there is no plastic film on the surface of the HSink.Make sure the fan speed control is working correctly .You may be able to rotate the Blower on the Hsink so it pulls air from towards the front of the case.