You cannot overclock in a 420 sort of.

To OC your video card you will need a program like Riviatuner.

There is no overclocking functions for the processor. The only way you could overclock it would be to do the Q6600 Pin Mod

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XPS-720's are also very overclockable.  The 700-710's have very limited o/c abilities..

WW

I did the tape mod on my 420s Q6600 and have it running at 3.0GHz per core without issue.  No extra cooling was needed with my 420.

More info here:

http://www.ocforums.com/showthread.php?t=546760

and

http://www.pbase.com/sjmarcy/image/92337793/original.jpg

Davet50, Really?  That was not my experience at all.  The 710 was much more limited.  I think I only had 3 or maybe 4 (pretty sure it was three) clock speeds to choose from on the 710.  The 720 has a lot more features as well.  The LED control has more options, the performance area of the bios is different.  I don't believe that there was a Performance Application Support Option on the 710.  Memory Cmd Rate on the 720, Speedstep isn't on the 710 is it?  I don't remember Virtualization being on the 710 either.  Now maybe Dell has updated the bios on the 710 since I have upgraded, but, in my experience, the bios was definitely not the same...

Respectfully,

WW

Well I still standby my statement. The 720 bios is a joke at overclocking period. The only overclocking options are  EPP/SLI for the ram and multiplier settings IF you have an extreme.

Now where is the ability to adjust the FSB how do you unlink the memory bus from the FSB where are the voltage adjusts etc etc. 

 I just feel that the things you list are not really related to overclocking support. Performance enhancements possibly. IMHO they are not overclocking options. 

I agree that compared to a third party motherboard such as Abit or Azuse that the overclocking options are much more limited.  My experience with the 710 MoBo was that I had to stay in the 2.xx Ghz range.  With the 720 I am able to run at 3.73 Ghz...