I use iStat to keep an eye on the temperature of my macbook pro. I noticed today that the temperature of my gpu diode dropped to -128 degrees Celsius. I decided that I should probably update my mac OS from 10.5 to 10.6. So I used my university's net install to install 10.6. I updated iStat to version 2.0. Then I noticed that GPU diode does not even show up in the menu. Therefore I downloaded Temperature Monitor and the GPU diode still does not show. However the GPU diode will sporadically show up. however, it has not shown up in a while now. I can still see the temperature of the GPU heatsink however. Does this mean that the GPU diode is bad? Or did the mac os X disable the reading of the GPU diode? If the GPU diode temperature sensor did go bad, is there any problems with running the laptop without getting it fixed? Any help with this matter would be very much appreciated.