A processor, system and/or techniques are disclosed for prefetching data streams in a processor. A prefetcher issues a plurality of requests to pre-fetch data from a stream in a plurality of streams; evaluates a confidence level of at least the first request based on an amount of confirmations observed in the stream; and assigns at least a first more aggressive prefetching ramping mode or a second less aggressive prefetching ramping mode based upon the confidence level of a thread associated with the prefetch request, wherein the prefetcher has one or more probationary states and is configured to transition between the first and second prefetching ramp mode by entering at least one of the probation states wherein the prefetcher continues to operate in the first prefetching ramp mode. In another aspect, the prefetcher may transition to the one or more probation states after a number of cycles.