AnandTech's Evan Lieb has squashed the hopes of many Intel users. According to his news report motherboards based on 865PE and 875P chipsets are among those not compatible with the first Prescotts. After meeting with a manufacturer in Los Angeles yesterday, we were told that the first batch of Prescott processors will not be compatible with any motherboard currently available on the market today. Before Prescott undergoes a complete socket overhaul in Q2 2004, all Prescott processors will be of the Socket 478 variety, shipments of which will start in early Q4 of this year. But due to a mandatory voltage regulation spec change from VIN 1.0 to VIN 1.5, these Socket 478 Prescott processors will not be compatible with any Socket 478 motherboards. We know of many users that are currently purchasing motherboards based on the assumption that, because Prescotts will be Socket 478 until Q2 next year, current Socket 478 motherboards will be compatible until then. However, this assumption is highly unlikely to be true based on the information we were given on Wednesday. Intel and motherboard manufacturers may be able to find a workaround, but we wouldn't count on it. Update: Maybe there is still hope... Overclockers.com dug a bit deeper than Evan Lieb did, when talking to the manufacturer. Although it is not impossible that there are current i865/i875 motherboards that can't support Prescott, the chance is high that future revisions will: 1) The technical terms used in the article that are referred to as new standards aren't. "VIN" stands for "voltage input" and is measured in voltage. "FMB" merely means Intel motherboard design standards, basically electrical and thermal requirements. 2) All relevant Intel documentation indicates that Northwood/Prescott motherboards are not only possible, but assumes that most if not all will. For instance, the Intel datasheet for the 875P chipset (initially released April 2003, revised May and June 2003, has the following subheading: "For Use with the Intel Pentium 4 Processor with 512-KB L2 Cache on 0.13 Micron Process and the processor code named Prescott (Processor Signature of 0F3xh)." (Don't worry, 865 owners. Anything said or linked below about the 875P is found in Intel's 865PE datasheet, too.) These datasheet talks a whole lot about Prescott. While Intel recommends that 865/875 mobos be made compatible with Prescott, it does not require it. It does say that 865/875 boards must support the VRD 10.0 (this is a name change for the VRM standard, see page 24 of the datasheet mentioned above) standard. The VRD 10.0 provides for voltage down to 0.8375. Prescott is supposed to have a default voltage of 1.225V. Motherboards that are supposed to support both Northwoods and Prescotts will need a little extra circuitry to identify the processor type and provide the correct voltage (and voltage slope), but Intel describes just how that can be done.