The only compatible motherboards with the e6300 processor are the ones posted on this site:
The 955x chipset based motherboard you have (either Intel or a third party one) may not be designed to support Core2 Duo processors just because of design limitations. Keep in mind that the compatibility is not determined by the socket type or the fact that the motherboard already support a really similar processor.
Even if your system has a lga775 socket does not make your system compatible with all 775 processors, basically if the system BIOS does not have the proper micro code to handle the processor, even if all specifications are met, the system will not work and will not be compatible.
End of interactive support for Intel products with chipset 955x was announced by December 2007.If you want to improve the last BIOS release, try to work with Intel Integrator Tool Kit 220.127.116.116. Simply open a folder and download iflash BIOS for your motherboard, BK95510J.86A.2049.IB.EXE, and extract it. Use SW.EXE to extract itk archive. With Integrator Tool Kit browse you itk archive, BK2049C.ITK.
I do not if it could work for using Core 2 Duo processors, but enable Core Multiplexing Technology, adjust FSB Default, and CPU VID to 1.325V. Also, you can enable to use 800MHz memory too, and good luck.
If somebody tested it, please let us know.
Warning: Use of unsupported processors may result in improper operations, damage to the desktop board or processor, or reduced product life.
reading your post, I discover I have same question with I955X but about upgrade from a Prescott P4 3.2Mhz to a E5800!
So, finally did you do the upgrade to E6300?
I am using a Desktop HP xw4300 (i955X rev. 00 & 82801GB (ICH7/R) rev. A1)
and I want to upgrade with an E5800 because same frequency and FSB the running P4 640.
So, like fenixconnektion, I am thinking documents from HP and Intel were written when C2D were not yet available!
it seems possible to upgrade from P4 641 to E4700 on a P5LP-LE ASUS motherboard with a 945G chipset!
Main diff between 945 and 955 is about ECC memories
So, is the Integrator Tool kit only for Bios on Intel motherboard or all (embedding Intel CPU&chipsets of course...)?