GDDR has high bandwidth but limited capacity. Regular RAM is the opposite, leaving typical APUs memory bandwidth starved.
Both types of processor perform much better with linear access. Even for data in the CPU cache you get a noticable speedup.
The primary difference is that GPUs want large contiguous blocks of "threads" to do the same thing (because in reality they aren't actually independent threads).
Both types of processor perform much better with linear access. Even for data in the CPU cache you get a noticable speedup.
The primary difference is that GPUs want large contiguous blocks of "threads" to do the same thing (because in reality they aren't actually independent threads).