I have ended up here because DELL and Intel have not answered my question
and I need some information from someone that fequents here

I have a system which is a Dell Dimension 8400, it has a 925X chipset
motherboard and was wanting to know what is the maximium CPU that I can
install in this system.

Socket is LGA775

I know for a fact from Intel's website that I can install processor number
660 and 672, but I can not buy the 672 here in New Zealand. I can buy the
660 and 670 processor but Intel's site doesn't show the 670 as supported but
other people say it will work.

Anyone here can help me?

Website listed below that shows which CPU will support which Chipset
http://indigo.intel.com/compare_cpu/showchart.aspx?mmID=873036,867280,873040,878
534,867285,878535,867289,878536,867290,878537,867291&familyID=1&culture=en-US

Email reply from Intel about my question

Thank you for contacting Intel(R) Technical Support.
As you can imagine, we receive many questions from customers regarding

compatibility between our processors and their computer systems.

We do not, however, maintain such information as doing so would be an

extraordinary endeavor given the wide array of motherboards currently on the

market. We rely on the motherboard and system manufacturers to maintain such

compatibility information, as their testing would require the use of our

processors (but not vice-versa). The board must be validated for the power
and

thermal specifications of the processor. The manufacturer must release a
BIOS

update for the board with explicit support for the stepping and frequency of
the

processor. They should also provide any configuration changes or updates

specific to the board.

Upgrade and compatibility information is specific to the motherboard, and it

MUST come from the motherboard or system manufacturer.

Please contact the system or motherboard manufacturer for further assistance
on

this matter, in your case DELL.

Email reply from DELL about my question

For your information, Dell does not offer processor or motherboard upgrades
for purchase as discreet items, nor does Dell recommend upgrading the
processor or motherboard in any given system; therefore, Dell cannot support
systems in which the motherboard or processor has been upgraded through
third-party services or products.

Hence, we are unable to determine or verify the compatibility of the
processor to the motherboard.