Really? oh good, thought i'd done something wrong!
System temp seems fine with the 120mm fan blowing in through the front and 2 x 80mm fans exhausting at rear, disconnected the 2 side fans! Just spent an hour on GTA: San Andreas and Sensor 2 is showing 30°c for system temp and 45°C for CPU so it's better than the duct I made (with stock cooler mind!) as I was getting about 43°C idle with that!
Cheers Zing, Alien and Keith and other contributors for all the help and advice, can we really put this thread to bed now?
