Filed under: DesktopsThere's all the makings of a class-A debacle over at AMD headquarters, as it turns out that the chip maker's quad-core Phenom processors are incompatible with some popular motherboard chipsets. Due to a thermal frequency mismatch, the 125-watt 9750 and 9850 CPUs don't play well with 780G-based mobos -- which are designed for AMD's less power-hungry 9600 and 9550 processors. Instead, AMD warns that its quad-core processors should be paired with the company's 790 chipse