unless you suppose it actually throttled to below base freq, which surely shouldn't happen that fast. Might be worth watching the CPU frequency while doing the test though.
Wouldn't expect to see such linear progression if that were the case. Steps, over a relatively long period of time, would be the likely pattern, no? Same goes for some other process fighting for resources. Every iteration requiring what appears to be a fairly constant increase in execution time (2-5ms on every iteration) seems an unlikely pattern unless the two processes are linked in some way, I would think.
