try using MSI afterburner. i reccomend a temperature up to 80ºC. however, whenever the temperature climbs up to 100ºC the card automatically stops working to prevent damage.
despite it is much powerfull than ati graphic cards, do not consider the absolute mining power as an indicator because every one who buys an asic minner is buying powerfull minning hardware. you should consider the relative minning power equipment. for example, the lowest mining power (5 GH/s) in the future will be extremely low compared to the 60 GH/s and even less compared to the 1500 GH/s.
i'm really interested in this post because i have the same problem: i keep getting the "IOError: [Errno 2] Noch such file … : phatk.cl". How do i modify the bitminer*.py? Please explain me step by step as I am quite new at bitcoin mininng.