The P4 Extreeme Edition has a 512KB Level 2 cache PLUS a 2MB Level 3 cache. EE has a 20 stage instruction pipe compared to the 31 stage pipe in the Prescot. The prescott has a 16KB level 1 cache compared to the EEs 8KB level one cache. So for your $1000 for your EE, you get a processor with approximately the same performance as a $500 P4 560 (3.6Ghz Prescott). According to Intel the EE's heat dissapation is 102 watts vs the Prescott's 103.