Hi to everybody!
I'm performing some benchmarks to compare discrete systems (GPU separated from CPU) with APUs under various conditions/algorithms.
At the beginning, I thought that "APUs are cool" because:
1) The cross-domain (CPU<->GPU) accesses and data-transfers latency/bandwidth are not architecturally limited by the PCI-e bus
2) The data can be passed between the CPU and the GPU without any copy (if properly allocated in OpenCL)
Anyway, recently someone told me that mapped cross-domain accesses can be performed also in discrete systems through the PCI-e bus, preventing from copying data.
Therefore, I'm actually not sure that the second reason why "APUs are cool" is totally right.
Can somebody help me to clarify this aspect?