Pentium 4 3.0 E GHZ, what is this E?

Answer 1

It doesn't really stand for anything in particular, just a part of the name. I can tell you that on a Pentium 4 3.2E and Pentium 4 3.2F, the E denotes that it is socket 478 and the F denotes socket 775. However they didn't make a 3.0 for socker 775, only 478, so the E is actually unnecessary.