Some motherboards slated to use quad-core Yorkfield processors are saddled with compatibility issues that may result in delays.
This, according to a report on the x86watch web site. The motherboards in question use Intel's upcoming 45-nanometer Q9550, Q9450, and Q9300 processors (otherwise referred to as Yorkfield non-Extreme).
An Intel spokesperson responded: "The 45nm Core 2 Quad launch is planned for Q1'08, and we are still on track for that." Rumors have been circulating that Intel is delaying Yorkfield non-Extreme processors strictly because, some theorize, competition from AMD has dwindled--due to quad-core Phenom and Barcelona delays--to the point that Intel saw no compelling reason to bring out new desktop processors.
Actually, there appears to be a more practical reason behind the delay, according to reports. Sources at Taiwan motherboard manufacturers are citing problems with the front-side bus (FSB) on certain boards that would use the Yorkfield non-Extreme processors. More specifically, mass-market four-layer boards, such as some P35-based boards, may have "noise" and stability issues, according to PC Watch which cited Taiwan motherboard vendors.
High-end, six-layer boards, such as those that use the X38 chipset, do not appear to have any FSB issues, according to the report. Consequently, high-end (six-layer) boards based on Intel's Extreme QX9650 do not have the issue, but lower-end boards using upcoming Yorkfield non-Extreme chips could potentially have issues. Apparently, Harpertown and dual-core Wolfdale boards do not have issues.
Finally, what rumors and reports seem to be missing is that Intel is not necessarily intentionally delaying these processors only because it believes that AMD is not competitive. The more plausible reason is that Intel believes that it has breathing room to fix the issue because of the AMD Barcelona and Phenom delays. The Intel fix may take one to two months, according to reports.
From x86watch web site