I have a powerful HP comuter with Q9550 (Core 2 Quad CPU). It seems that there is only one MMX/SSE unit shared between all 4 cores.
The reason I think so is the following. I am running a simple program that usses SSE-2.
- Running 1 thread achieves 300MB/s.
- Running 2 threads achieves 150MB/s per thread.
- Running 4 threads achieves 75MB/s per thread.
My laptop with T7250 (Core 2 Duo CPU) exhibits the similar behavior.
Is it true that Core-2 CPUs contain only one MMX/SSE unit?