I am looking to buy a P4 cpu 3GHz or upwards and have found that some have a E after the speed rating, I have trawled Intels web site and nowhere do they explain what the differance is. Now the only differance I can see is 1Mb cache instead of 512K, what makes me wonder if this is the only differance is that the E ver is cheaper than the non-E version, both are748 socket, what am I missing here?