Approximate cost to access various caches and main

Question

Can anyone give me the approximate time (in nanoseconds) to access L1, L2 and L3 caches, as well as main memory on Intel i7 processors?

While this isn't specifically a programming question, knowing these kinds of speed details is neccessary for some low-latency programming challenges.

Answer 1

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The bottom line?

Any low-latency motivated design has to rather reverse-engineer the "I/O-hydraulics" ( as 0 1-XFERs are incompressible by the nature ) and the resulting latencies rule the performance envelope for any GPGPU solution be it computationally intensive ( read: where processing costs are forgiving a bit more a poor latency XFERs ... ) or not ( read: where ( might be to someone's surprise ) CPU-s are faster in end-to-end processing, than GPU fabrics [citations available] ).