Thanks for the reply,

I did read that thread and at the bottom "manydimensions" said this:

"The fastest processor you can run is the Pentium D 965 EE 3.73GHz  at a cost of around $600+ for the OEM CPU."

That made me think I had found the answer but then "xcator" replied and said this:

"you may be able to boot a 955EE or 965EE in a Gen 5 but it will not work at the right clock speed due to bios limitations.  bios overclocking will not work right either.  An 840EE works and will overclock to 3.6 in the bios and should be stable.  It's been reported that a Pentium D 945 and 950 will work with bios A04. "

That threw in the little bug of doubt.  I really don't know what the max CPU I can install in my system at this point.

You know what's funny?  When I clicked on your google search link I saw a bunch of links that I had already visited.  I've looked at this for quite some time without actually seeing someone from Dell come out and say what the max CPU is for my machine.

Hi Flyle,

Did you already see this thread in your search?

Here's a Google search for you, too.