Parallel data transfer to increase bandwidth for accelerated processing devices

Techniques for improving data transfer in a system having multiple accelerated processing devices ("APDs") are described herein. In such a system, multiple APDs are coupled to a processor (e.g., a central processing unit ("CPU")) via a general interconnect fabric and to each other via a high speed interconnect. The techniques herein increase the effective bandwidth for transfer of data between the CPU and the APD by transmitting data to both APDs through the portion of the interconnect fabric coupled to each respective APD. Then, one of the APDs transfers data to the other APD or to the processor via the high speed inter-APD interconnect. Although data transferred "indirectly" through the helper APD takes slightly more time to be transferred than a direct transfer, the total effective bandwidth to the target is increased due to the high-speed inter-APD interconnect.