With all this talk about the xBench and Geekbench numbers I'm leaning towards overclocking my main machine which has the quad core Q6600 (currently at stock 2.4Ghz).
I know our board's BIOS has that easy to use overclocking gui, but how did you proceed with that? I mean, did you first go up to 2.5Ghz and see how it runs and then go higher? And also what exactly did you change in that screen? They have settings for "CPU Clock Ratio" and "Fine CPU Clock Ratio", etc.
with the Q6600 (G0 stepping, 9x Watt cpu) (if you have windows installed, not vmware, use cpuZ to be sure you have G0 )
the speed I consider the best for my machine is 3.2Ghz if I go higher I have to increase the vcore for stability, but then the temperature starts to gets too close to the intel "safe" for Q6600 G0 stepping, which is 71°C for Core temp (for previous stepping 1xx Watt cpu the max safe temp is lower)
max safe vcore is 1.5 according to intel (but my air cooler doesn't keep the temperature lower)
CPU temp (not core) the max safe temp is 60°C
If you have installed a speaker for the motherboard you can set an alarm in the bios for when the cpu temp gets to 60°C (which in my case rang when the core temp was at about 72°C but I was testing 3.4Ghz then)
so I guess CPU temp will usually be 10°C cooler thann core temp
use a temperture monitor to check the temperature
to run at full load download mprime (it prime 95 but for mac os), it's a terminal utility...
first time you run it ask you some question, tell it you want to benchmak (it will ask for it), then keep the default value (just press enter), then afterwards second time you run it, just use the option 15 in the list (and keep pressing [Enter] about 4 times to use and accept the default values)
if the core temp gets above 71°C cancel the process ([CTRL]+[C])
now that you are aware of the requiered safety if you don't want to burn you CPU
now the BIOS part:
just enable manual option to be able to set the FBS
type in 333 for the FBS to get 3Ghz on each cpu core
depending on your ram, using the ram ratio keep it below a 50Mhz overclock, any ram should handle that easily
you'll see there are same ratio option for different FBS speed, I just use the closeset one to the FBS....
reboot and enjoy the speed...
unless you are doing cpu intensive application you won't really see a difference
(I do 3D rendering on this machine and every single 100Mhz overclock gives me a nice increase in render speed)
I would set the vcore to your default value manually, on mine it's 3.25xx v
so that it doesn't increase too much automatically...
with my cpu I can keep the default vcore up to 3.2Ghz after that I have to increase it (but that is the main factor of temperatue increase)
if you want to go above 3Ghz let me know, you'll need to change more option (like north bridge voltage)
if you have a G0 stepping, you should be able to get up to 3.6Ghz, but you'd need water cooling...
at 3.4Ghz it rise up to around 75°C so to much for me
3.3Ghz is an option for me with my cooler but rises up to 68°C so I don't want that
at 3.2Ghz at ususally doesn't go above 63°C
but if you don't have a G0 or latter stepping those temperature are too high