make sure your motherboard supports the 45nm E6300 and not the old 65nm one. the 65nm version runs at 2.13 GHz if I remember correctly.
The 65nm E6300 is a Conroe Core2Duo that runs at 1.86Ghz... have it myself
Low stock clock speeds but great for OCing.
Core2Duo > Pentium Dual Core > Pentium D
E6300 P-Dual Core > E6300 Core2 (lower clock speeds) > Pentium D