Cheap mass-produced USB peripheral chips tend to contain x51 core for control and some kind of high-performace datapath full of DMA and FIFOs for the actual dat

Cheap mass-produced USB peripheral chips tend to contain x51 core for control and some kind of high-performace datapath full of DMA and FIFOs for the actual data if the peripheral in question actually needs to move large amounts of data around. Having ARM core in there is somewhat rare because of the costs (both in terms of the IP license and in terms of silicon footprint).