I am looking for a socket 478 motherboard for my old 3GHz Pentium 4 HT processor & found a 865chipset board which claims DDR2. But I am not sure if 865 really supports DDR2 ?
The Intel 865 chip-set doesn't support DDR2.
They didn't introduce DDR2 support until the 915 chip-set generation.
Check out Wikipedia's info on it here.
Intel's info on the 865G chip-set's memory compatibility (specifically on the Intel D865GBFL board) is here:
Hope that helps.
The specifications pdf on page 13 (Under revision History) says it supports DDR(type1) 266, 333, 400, no mention of DDR2