Ok, seems you are working with a board with an intel 865 chipset, SATA(1.5) support and support for 48Logical Bit Adress. (This allows Drives larger than the 128/137gb limit)
And the List of Supported CPUs for it:
And if your board is NOT the revision required for any of the CPUs listed I'd say
that Intel generally knows what they are talking about and that you need to choose
carefully from the list of CPUs for ones that are stated as working with your specific revision.
I have several Socket 775 boards that are "one revision short" of being able to run the CPU I have several of, a Pentium D 945 dual core 3.40MHz CPU SL9QQ, they
will support the different "stepping" SL9QB.
If you really want to upgrade I'd suggest you go shopping for a newer Motherboard that supports a C2D CPU because that would really perform compared to any single core CPU.
C2D CPU's will easily outperform any Northwood or Prescott CPU with even a 75% higher clock speed.... and by a significant margin.