Intel P4 is a CPU. LGA775 is the socket of the MB. Depending on BIOS support, the CPU will be compatible with the motherboard. Is the CPU necessarily installed in the motherboard when purchased? No. Whew.
The question you are asking is not clear. I think you are asking which specific processor is supported by each specific MB on the list. Be specific.
Which Intel processor are you referring to?
Then which specific Motherboard are you refering to?
The motherboard's BIOS would have to support the Intel CPU you are referring to. Otherwise, No. All of the Motherboards in the list do not support all Intel CPU's.
Each MB has an online product page which lists the specific Intel CPU's supported as well as the BIOS version required for suport.
My comment: Your question 'there is a list of p4 lga775 does that mean all the mobo there are supported' is 'too generalized' and out of context. Which specific CPU are you referring. No. The P45 boards on that list do not support 'ALL' pentium 4 processors for examnple.