Intel Core 2 Duo E6600 vs Pentium 4 2.66 GHz Core 2 Duo E6600 vs Pentium 4 2.66 GHz specifications comparison The charts below compare the most important Intel Pentium 4 2.66 GHz and Core 2 Duo E6600 characteristics. These features, along with an IPC (instructions per cycle) number, determine how ..