Here you go. Data should be your best friend:
http://img62.imageshack.us/img62/4013/45uo6.jpg
Add to these numbers some performance boost from the faster FSB @1333MHz of Yorkfield, because Q6600 has FSB @1066MHz.
And BTW, pay attention at the power consumption and the temperatures.
You may roll your eyes over and over, but indeed quad core is obsolete for general users. It may be of use only if you are running a very specific task like rendering and encoding/decoding. How many apps do you know that can utilize 4 cores? Also, how much % of the time your CPU is idle?