It's time to place your bets. What's going to create the most buzz this year? Heavy odds say it will be multi-core processors and multi-core system-on-a-chip (SoC) solutions. Some multi-core products will be implemented as standard products, while others will be crafted as application-specific standard products (ASSPs). Still other implementations will be full-custom application-specific ICs (ASICs) specific to a single customer.
It's getting harder to maintain the power envelope in which commodity and server CPUs must operate due to ever-increasing clock frequencies. By using two lower-speed CPU cores on one chip, however, dual-core processors from Intel and AMD can deliver better throughput while consuming less power than a single higher-speed core.
In addition to dual cores, Intel's hyper-threading technology—used on both single-core CPUs and the dual-core Pentium Extreme Edition—enables the dual-core chip to run two instruction threads on each of its two cores. As a result, systems can run four simultaneous programs.
Even the PowerPC is moving to dual cores. Used by Apple Computer in many desktop and portable systems, the popular Altivec processor soon will have a more highly integrated dual-core cousin, the MPC8641D. Optimized for network-related applications, each of its two full e600 PowerPC cores will boast a 1-Mbyte L2 cache that packs error-checking and correction.
The MPC8641D also will feature the Altivec vector-processor extensions. The chip integrates a system controller and a PowerQUICC network subsystem that includes four Gigabit Ethernet ports, serial RapidIO ports, and a PCI Express interface.
Dual-core CPUs are just the starting point. Intel recently revealed a roadmap with at least one quad-core design on the drawing boards. And Sun Microsystems' latest UltraSPARC CPU, code-named Niagra, offers eight cores. Targeting servers and blade servers, each one of Niagra's cores can run four instruction threads for 32 instruction streams overall, as if 32 processors were available to the operating system.
Multi-core processors aren't new, especially in the embedded market. Network processors have taken advantage of single-chip multiprocessor solutions for years. But it's now possible to integrate over a billion transistors on one chip. Therefore, designers can implement much more complex cores than previously possible, as well as provide substantial multilevel caches and other resources. The final result will be chips with supercomputer-class performance.
In ASSPs and ASICs, multi-core CPUs are making their way from the industrial embedded space into mass-market consumer products. For example, Microsoft uses a custom triple-core PowerPC-based CPU as the heart of its Xbox 360.
Partnered with IBM and Toshiba, Sony developed the multi-core Cell processor. It combines a PowerPC core that serves as a system controller with eight identical compute engines operating in parallel to handle graphics and other computation-intensive applications. The Cell processor also will find homes in non-gaming applications. Mercury
Computer Systems is developing several compute platforms based on arrays of Cell processor chips. The first is a blade server based on two Cell processors (see the figure). The latest system, the Turismo, delivers 800 GFLOPS in a 600-in.3 footprint. Multiple Turismo boxes can be combined to provide supercomputing solutions.
ASICs PUT IT ALL TOGETHER
ASIC vendors, fabless chip design houses, and OEMs must rely on every aspect of semiconductor technology to craft such highly integrated solutions. These companies require advanced processes and metallization schemes to integrate and interconnect the billion or so transistors; new transistor structures to achieve faster switching times and lower power drains; IP libraries to reduce design time; and design tools to help assemble, lay out, and verify the design.
AMI Semiconductors, IBM, and LSI Logic, for example, provide full ASIC implementation services. They offer a one-stop solution with libraries, design-tool flows, and full chip manufacturing from silicon to packaging. TSMC, UMC, Chartered Semiconductor, Silterra, and SMIC provide foundry services that come close to the services supplied by ASIC vendors, but they don't directly offer design services. Large OEMs, including Fujitsu, Freescale, and Toshiba, provide ASIC services much like those of ASIC suppliers. Or, they can offer foundry services.
Many of these companies have chip-fabrication services using 90-nm process rules. A few offer design kits for customers to develop chips based on 65-nm process rules. Chartered, which licensed IBM's high-performance silicon-insulator (SOI) technology, offers that process in its foundry. Freescale uses its SOI manufacturing capability for standard products and as a resource for ASIC/ foundry customers.