AMD yesterday confirmed that high-end Phenom processors with a 125W TDP have compatibility problems with 780G based motherboards:
"What people have done, mistakenly, is paired a 780G (chipset-based) motherboard with the higher frequency Phenom--the 125-watt Phenom," said Jake Whitman, an AMD spokesperson.
Whitman is referring to the fact that the high-end 9750 and 9850 Phenom processors have a Thermal Design Power (TDP or thermal envelope) of 125 watts versus the lower-end 9600 and 9550 models that have a TDP of 95 watts. The higher-watt parts will not work with motherboards that contain the 780G chipset. The lower-end models do not have these TDP issues.
"They've taken an enthusiast-class quad-core part and paired it with a mainstream motherboard," Whitman said. "And not all motherboard manufacturers have tweaked their boards to support a 125-watt TDP." Whitman says that AMD's 790 chipset--not the 780--should be paired with the 9750 and 9850 processors and that a number of motherboard makers are already doing this.
"We've never made claims that 780G motherboards are enthusiast-class motherboards," Whitman said.