As of July 22 the quad cores are supposed to come down in price by fifty percent. The dual cores will be reduced by twenty to thirty percent. The e6600 and e6700 have 4Mb of L2 cash. The q6600 has I believe has 2Mb per core or 8Mbts of L2 cash. I cant really answer your question completely as I have an e6400, a evga 122ckn68a2 board and have my e6400 FSB at 1400Mhz or 2.8Mhz up from 2.13Mhz. I spent twenty years in electronics so hardware is easy for me. I would wait for the q6600 to come down in price before you make your decision. Also I have a Zalman 9700 fan and I highly recommend this fan.Also your ram speed is also important. I want to upgrade to 1066Mhz ram from 667Mhz ram. The higher the ram speed the faster you can overclock. Of course their are diminishing returns to just about everything. Heat or more wattage for increasing FSB speed. Best of luck. Also with my e6400 c2d it usually used only 1 percent or less of cpu capacity unless I run Quake 4 and than it goes up to fifty to eighty percent. If you run alot of programs, P2P, browser, games, the more the cpu capacity get utilized. Bottom line dude I will buy a quad sooner or later. Man is this an expensive hobby or what. Later.