Can anyone tell me any specifics on what method Claymore uses to get gpu temps?

I'm trying to troubleshoot a 7950 reference card that recently started reporting high temps to Claymore, but aticonfig --odgt fails to retrieve temp (or clocks). Claymore gets the temperature, but the card is actually about 20C cooler than reported temps. It'll hash; and temp seems fine best I can tell with an infrared thermometer on the PCB & comparing with identical cards in the rig.

Anyone suggest a possible fix or route for troubleshooting? I've flashed original bios, i've tried down-volted and down-clocked bios and all get the same overheating results.

I can use claymore's low intensity mode (-li 50) and turn the clocks down to 850, 1000 and use -asm 2 and it'll hash at about 30 sol/sec but says it's 80C and really isn't.