Platform Trends: Intel's Roadmap Highlights Route 45nm

The big news this week was Intel's briefing on its upcoming processor architecture. The path to from its current 65- to 45-nanometer process engineering was the main emphasis -- while archrival AMD is still making the transition from 90nm to 65nm silicon, Intel has more than fifteen 45nm projects in the works.

These all use what Intel calls the hafnium-based high-K-plus-metal-gate transistor design, which promises both higher performance and greater energy efficiency. Enhancements to the base Core 2 architecture were also discussed, as was Intel's proposed CPU lineup through 2008.

The company restated its goal of providing a new or enhanced microarchitecture every year, specifying the "Penryn" core as its entrant for 2007. Penryn-based processors will see daylight in the second half of the year, after which Intel vows to ramp up its 45nm production and take things to a whole new level in 2008. By then, Intel hopes that its 45nm processors will be as ubiquitous as its 65nm parts are today -- staying, in other words, a step ahead of AMD.

The Penryn is Mightier than the Sword

The Penryn is an enhancement to today's Core 2 architecture, with the most obvious improvement being the smaller process technology. This will permit a dual-core die size of 107 square millimeters -- 25 percent smaller than current 65nm chips -- while cramming 820 million transistors into the quad-core replacement for today's 582-million-transistor Core 2 Quad. As for power requirements, Intel declares they'll be consistent with, if not lower than, those of today's Core 2 models.

Higher clock speeds are a natural by-product of die shrinks; while staying within today's thermal and power envelopes, Intel is planning to hit 3.0GHz and higher speeds at introduction. The 45nm core also allows Intel to increase the Core 2's dynamically shared Level 2 cache -- 6MB for the dual-core Penryn and 12MB for the quad-core. The degree of cache associativity has also been improved, which can help cache efficiency and overall CPU performance.

Add microarchitecture optimizations that raise instructions-per-cycle rates, and the Penryn promises to outrun today's Core 2 at the same frequencies. When you factor in the higher clock speeds, Intel's upcoming 45nm dual and quad-core processors should upstage and replace today's "Conroe" core quite handily. In some ways, it's reminiscent of the mobile transition from the Core Duo to the Core 2 Duo and the resultant 20-percent performance jump at the same clock speed.

System bus speeds will also increase to 1.33GHz, as will memory speeds -- logically to DDR-2/1000 or higher -- in order to accommodate the greater CPU bandwidth. The Penryn will introduce additional multimedia, gaming, and graphics instructions to the existing SSE4 set, potentially giving the processor greater multimedia muscle. The performance of Intel's Virtualization Technology has been improved, while the divider speed has been doubled through a technique called Radix 16. A mobile Penryn will include market-specific features such as a super-battery-thrifty Deep Power Down state and Dynamic Acceleration Technology for improved single-threaded performance.

Penryn processors will not only share the basic Core 2 architecture, but will enter the market branded as such: Desktop and mobile CPUs will continue to use the Core brand, while server and workstation chips keep the Xeon name. Initially, there will be six different Penryn models -- dual- and quad-core desktop and server processors plus one dual-core mobile part and an ultra-high-end server model. Later, this will expand to the projected lineup of 15 parts.

Nehalem for 2008

The Penryn may be the last word on the Core 2 design, as Intel's follow-up -- codenamed "Nehalem" -- will feature an entirely new processor architecture. If the Core 2 blew you away, prepare to be dazzled. Intel is promoting Nehalem as a "dynamically scalable" architecture. This means that virtually every part of the processor -- including cores, cache, threads, interfaces, and power -- can be dynamically allocated based on performance, power and thermal requirements.

The memory interface has been totally revamped; in fact, Nehalem will be the first Intel desktop CPU to include an integrated memory controller. Memory bandwidth is one area where AMD processors' integrated memory controllers continue to hold an advantage. That's only been exacerbated with the move to multicore processors, but it appears that Intel is primed to level the playing field.

Not only that, but the Nehalem will support DDR-3 system memory at clock speeds up to 1.33GHz and with multiple memory channels per CPU. Other improvements include a multilevel Smart Cache architecture for higher performance and greater scalability. Exactly how this plays out is still unknown, but logic entails a hierarchy like the standard Level 1, 2, 3, and 4 cache format.

The projected roadmap contains references to single-, dual-, quad-, and even octo-core Nehalem processors, capable of handling from one to sixteen simultaneous threads. The Nehalem also heralds the return of a Hyper-Threading mechanism -- what Intel now calls simultaneous multithreading will allow each core to handle two instruction threads. Core-based multithreading is a viable technology, but after Intel got scared away with the ill-suited Pentium D Extreme HT models, it skipped the Core 2 line.

This is one scenario that AMD has no real answer for; if Intel plays its cards right, the Nehalem could be one formidable adversary. It's also the obvious reason for this week's press briefing -- Intel enjoys speaking from a position of power and advantage, and now feels its upcoming 45nm technology will create an even larger gap between the two companies. Perhaps Intel was right to disregard the buzz about a possible Nvidia buyout and concentrate on its PC processor and platform business.