The document discusses the differences between CPUs and GPUs in Raspberry Pi systems-on-a-chip. It notes that while GPUs were traditionally used for graphics, modern GPUs are capable of general purpose computing like CPUs. The Raspberry Pi system-on-a-chip integrates a CPU, GPU, and other components. The GPU in the Raspberry Pi is made by Broadcom and can be used for general purpose computing through an approach called GPGPU (general-purpose computing on graphics processing units).