The delay of Intel Corp.’s new breed of microprocessors manufactured using 45nm process technology was not caused by an error in chips, but was necessary to ensure compatibility of new central processing units (CPUs) with already available mainboards.

As reported, Intel decided to postpone the commercial launch of its microprocessors made using 45nm process technology recently due to issues with processor system bus (PSB). According to a news-report from PC Watch web-site, the issues with quad-core code-named Yorkfield processors occur on affordable mainboards that utilize 4-layer print-circuit boards (PCBs) and do not affect expensive platforms that are based on 6-layer PCBs. As a consequence, the world’s largest producer of x86 processors decided to create a new version of its chips to retain compatibility with mainstream motherboards.

Nowadays the majority of Intel’s quad-core microprocessors for desktops – which consist of two dual-core dice on a single piece of substrate – utilize 1066MHz processor system bus and only two Intel Core 2 Extreme processors QX6850 and QX9650 use 1333MHz PSB. Since Intel’s “extreme” chips that retail for over $1000 a unit are installed into expensive mainboards, no problems occur. In fact, Intel Xeon processors, some of which feature 1600MHz PSB, also do not have any troubles with such high speed. But apparently current design of Intel Core 2 Quad microprocessors with 1333MHz bus made using 45nm technology results in excessive “PSB noise”, which prevents normal operation.

Since many mainboards based on Intel P35 chipset that are based on 4-layer PCB are already available and are utilized by large system vendors, it is hardly possible for Intel to ask motherboard makers to revise their designs. Typically, mainboard redesign can take several weeks and validation and compatibility processes may take up to two months. As a result, Intel has decided to slightly alter its chips so that they could work in existing infrastructure, the Japanese web-site reported.

The new quad-core microprocessors from Intel, which are now projected to emerge in February or March, are expected to be fully compatible with existing infrastructure.