I have a brand new Gigabyte P35-DS3R mobo and am considering either the Q6600 or the E8400.  I know the E8400 is the 45nm core, runs cooler and uses less power.  It also has the 1333 MHz bus.  The quad core 6600 just seems cool and hs very well rated.
 
If I overclock the Q6600, with the slower bus speed, will that make up for the faster bus speed on the Q6600?  Does bus speed really matter if they are OC'd anyway?  
 
Does the better cache on the E8400 lead to better performance overall?  I do mostly mid level gaming (mostly RTS games and MMORPGs), occasional video encoding, etc.  
 
Also, how is the P35-DS3R for overclockability?
 
Thanks!

Get the 8200 cpu and overclock  @3,5ghz at least
without any aditional voltage
Your gigabyte mb is pretty nice but p35ds4 is better even though it doesnt support ddr3 it has more features  
Gigabyte also has Easy tune which makes oveclocking realy easy though i prefer the old traditional way
As for the quad prossesor its ok but at 3,5 ghz it needs some voltage and e better cooler ,and its not that stable
FSB is crap too,i made some 3d bench with my 8200 with 2000mhz fsb overclocked of course and no real impact in games performace
The same results with ddr 2 at 533 and 1066  
I believe that the best cpu is the one with the higher clock and the dual core can hit at least 3,8ghz with a little more voltage (1,275v) and i nice cooler
 

as always said.higher of everything is better.so have highest CPU/FSB/Ram speed you can achieve stable to get the best out of it.
 
mavridisglas,i would like you correct your statement.in 3dmark it wont make a difference with higher FSB and ram.but if you use ram benchmark.a high speed ram with higher FSB will have higher score then high speed ram with low FSB.i think you dont know that the CPU and Ram are communicate through the FSB so higher FSB will allow bigger bandwidth to the memory subsystem.but you can really benefit from it if the application is so memory intensive.
 
with Tuniq or TRUE you can hit beyond 3.6ghz+ with stability.maybe sometime you get high VID or a poor mobo that restrict the OC potential of the Q6600.
 
to overclock the Q6600 is the best to select 8X multiplier to get the best performance out of the whole system with ram run in sync mode.

i dont see anything corrected,i was only refering to 3d mark
if games is what u care about all these fsb and memory speed is crap

but 3dmard doesnt replect the system performance.and by not getting the best out of his computer you completely missed the point of OVERCLOCKING.

As far as games go, the E class is a better choice. Now dont get me wrong the q6600 Is a very cool chip, I have one. For gaming I like my Heavily overclocked e6300 better.  FSB is a problem for intel's quads Q series cause when the two cores have to communicate they have to using the FSB. Get the E class now and by the time games are ready for quad and beyond intels new socket and multicore design will cream the Old Q class. In the respective benchies/apps.

I have an e6300 now and can get 2.8GHz out of it easy and stable, running 7x400.  
 
How much of a difference is the e8400 over the e6300?  I was pretty happy with my home PC until  I got an e6750 at work that seemed very fast.  

P35 runs at 1333mhz fsb natively, and reliably oc to 1600mhz. 1600mhz fsb = 3.6ghz on both e8400 and q6600. E8400 can easily oc beyond 4ghz, q6600 cannot effectively oc much beyond 3.8ghz. When both are bottlenecked at 3.6ghz, q6600 outperform e8400 even on older non quad optimized programs, due to background programs being moved to spare cores, thus freeing up 2 cores for dedicated use.

so many ppl ask the same question i even couldnt decide between the e8400 or q6600. ill give u my 2cents i went with the q6600 because i dont plan to upgrade for maybe 2-3years im not rich. more and more app will make use of the quads better later on, as of now e8400 will win by a little bit in games but i would rather be future proof. unless ur a HARDCORE gamer go with e8400 but future games the quad will do better.
the q6600 is quite overclockable i have mine running 3.0ghz no need to overclock more 3 ghz is enough for me. if u want the g0 stepping q6600 u can get 3.6ghz to 4ghz. hope i helped good luck with ur choice there both great cpu.