It is now confirmed that Intel is playing the same bad socket joke it is known for again and current platforms from a lot of mainboard makers will not be compatible with Intel Prescott processor coming out this Fall. According to roadmaps I have just seen, a huge Taiwanese mainboard maker will start to offer mainboards with appropriate features and capabilities to support Prescott in the second half of August.
All or almost all mainboards based on i865PE and i875P chipsets are not VRM10.0, FMB1.5-compatible, that is why you will not be able to use Intel Prescott chip on those platforms. As a result, mainboard makers have to redesign their products. Beginning from the second half of August, at least one mainboard maker indicates appearance of its mainboards revision 2.x that are compliant to FMB 1.5 of Voltage Regulator-Down (VRD) 10.0 Design Guide. See our July, 11th news-story for more information on the matter.
There is still no information about the nature of changes between FMB 1.0 and FMB 1.5 and what is not enough for current platforms to support the forthcoming Socket 478 chip. I am also not sure about Prescott support by mainboards based on third-party chipsets. In fact, mainboard makers have known that their current products do not support Prescott chips for weeks now, so, it is a mystery why, for example, ASUS still claims that their i865PE-based mainboard supports Prescott processor. Maybe they can guarantee it?