The Pentium® 4 Processor

March 5, 2002 Tuesday
Hamerschlag Hall 1112
4:00 p.m.

Doug M. Carmean
Principal Architect, Intel Corporation

This talk describes the main features and functions of the Pentium® 4 processor micro-architecture. We present the front-end of the machine, including its new form of instruction cache called the Execution Trace Cache. We also describe the out-of-order execution engine, including the extremely low latency double-pumped ALU (Arithmetic Logic Unit) that runs at more than 3.4 GHz. We also discuss the memory subsystem, including the very low latency Level 1 data cache that is accessed in just two clock cycles. We then touch on some of the key features that allow the Pentium 4 processor to have outstanding floating-point and multi-media performance. We provide some key performance numbers for this processor, comparing it to the Pentium® III processor.

The Pentium® 4 processor has 42 million transistors implemented on Intel's 0.18u CMOS process; with six levels of aluminum interconnect. It has a die size of 217 mm2 and it consumes 75 watts of power at 2000 MHz. Its 3.2 GB/second system bus helps provide the high data bandwidths needed to supply data to today and tomorrow's demanding applications. It adds 144 new 128-bit Single Instruction Multiple Data (SIMD) instructions called SSE2 (Streaming SIMD Extension 2) that improve performance for multi-media, content creation, scientific, and engineering applications.

The Pentium® 4 micro-architecture was designed to have an even deeper pipeline (about two times the P6 micro-architecture) with even fewer gates of logic per clock cycle to allow an industry-leading clock rate. Compared to the P6 family of processors, the Pentium® 4 processor was designed with a greater than 1.6 times higher frequency target for its main clock rate, on the same process technology. This allows it to operate at a much higher frequency than the P6 family of processors on the same silicon process technology. At its introduction in November 2000, the Pentium® 4 processor was at 1.5 times the frequency of the Pentium® III processor. Over time this frequency delta will increase as the Pentium® 4 processor design matures.

Doug Carmean is a Principal Architect with Intel's Desktop Products Group in Oregon. Doug was one of the key architects, responsible for definition of the Intel Pentium 4 processor. He has been with Intel for 13 years, working on IA-32 processors from the 80486 to the Intel Pentium 4 processor and beyond. Prior to joining Intel, Doug worked at ROSS Technology, Sun Microsystems, Cypress Semiconductor and Lattice Semiconductor. Doug enjoys fast cars and scary, Italian motorcycles.