On the x86 architecture, RAM is used by the CPU and the GPU has a huge penalty when accessing main RAM. It therefore has onboard graphics memory.
On ARM this is unified so GPU and CPU can both access the same memory, at the same penalty. This means a huge class of embarrassingly parallel problems can be solved quicker on this architecture.
Do you mind elaborating what is it about the difference on their memory models that makes a difference?
On the x86 architecture, RAM is used by the CPU and the GPU has a huge penalty when accessing main RAM. It therefore has onboard graphics memory.
On ARM this is unified so GPU and CPU can both access the same memory, at the same penalty. This means a huge class of embarrassingly parallel problems can be solved quicker on this architecture.