By what measure are modern AMD CPUs not an SOC (especially the APU models)? They literally can function without a chipset.
The chipsets are little more a PCI-E extender with some built in USB and SATA controllers connected to it.
The CPUs do perform some form of handshaking with the chipset, but after that is done, it does not care. This handshake is literally about being able to lock out certain on die features if you don't buy the more expensive chipsets. (Or partner with AMD to get access to an small 8 pin activator chip to unlock the features you need, and add your own PCI-E extender if desired).
The chipsets are little more a PCI-E extender with some built in USB and SATA controllers connected to it.
The CPUs do perform some form of handshaking with the chipset, but after that is done, it does not care. This handshake is literally about being able to lock out certain on die features if you don't buy the more expensive chipsets. (Or partner with AMD to get access to an small 8 pin activator chip to unlock the features you need, and add your own PCI-E extender if desired).