Prescott is the latest incarnation of the Pentium 4 chip, and contains a whole host of extra enhancements and differences.
"To avoid sacrificing performance, Intel improved the branch prediction in Prescott, including the addition of an indirect branch predictor. Intel also increased the L2 cache size to 1MB, as well as doubling the L1 cache size to 16KB. The instruction schedulers for x87 floating point and SSE were also increased to enhance parallelism in multimedia code. Other tweaks were also added to improve HyperThreading (simultaneous multithreading) performance."
Read all about this new processor here.