Intel Desktop Pentium 4 Willamette microprocessor family

New 478-pin micro-PGA package for desktop Pentium 4 microprocessors was introduced in August 2001 together with 1.9 GHz and 2 GHz versions of Pentium 4s. Almost full line of Willamette CPUs, starting from this Pentium 4 1.4 GHz, was also converted to use the brand-new 478-pin package. This package, compatible with socket 478 motherboards, had 35% smaller width and height, and 57% smaller package area than original Pentium 4 CPUs. This reduction in size was achieved by cutting distance between pins in half. The smaller package was the major change in socket 478 Willamette processors. There were also minor differences between socket 423 and 478 versions of Pentium 4 in electrical characteristics, maximum operating temperature and Thermal Design Power. All major CPU features, such as micro-architecture, size of cache memory, support for SIMD instructions, etc, stayed the same on socket 478 Willamette processors.