Yonah (microprocessor) - Advantages and Shortcomings

Advantages and Shortcomings

The Duo version of Intel Core (Yonah) includes two computational cores, providing performance per watt almost as good as any previous single core Intel processors. In battery-operated devices such as notebook computers, this translates to getting as much total work done per battery charge as with older computers, although the same total work may be done faster. When parallel computations and multiprocessing are able to utilize both cores, the Intel Core Duo delivers much higher peak speed compared to the single-core chips previously available for mobile devices.

The shortcomings of Intel Core (Yonah) are:

• The same or even slightly worse performance per watt in single threaded or non-parallel applications compared to its predecessor.
• 32-bit processes only. 64-bit processes are not supported. (See the Intel Core 2 successor, which is a 64-bit processor.)
• High memory latency due to the lack of on-die memory controller (further aggravated by system-chipset's use of DDR2 SDRAM)
• Limited Floating Point Unit (multiply/divide) throughput for non-parallel computations or single-threaded processes; this is due to the smaller number of floating-point units in each CPU core compared to some previous designs.

The Yonah platform requires all main-memory transactions to pass through the Northbridge of the chipset, increasing latency compared to the AMD's Turion platform. However, application tests showed Intel Core's L2-cache system is quite effective at overcoming main-memory latency; despite this limitation, Intel Core (Yonah) sometimes managed to outperform AMD's Turion.

The Sossaman processor for servers, which is based on Yonah, also lacks Intel 64-bit support. For the server market, this had severe consequences, since all major server operating systems already supported x86-64, and Microsoft Exchange Server 2007 requires a 64-bit processor to run.

According to Mobile Roadmaps from 2005, Intel's Yonah project originally focused more on reducing the power consumption of its P6-based Pentium M processor and aimed to reduce it by 50% for Intel Core (Yonah). Intel continued recommending the NetBurst-based Mobile Pentium 4 processors for high performance applications (although these were less power efficient and gave off significantly more heat) until the Yonah project succeeded in extracting higher performance from its lower-power-consumption design. The Intel Core Duo's inclusion of two highly-efficient cores on one chip can provide better performance than a Mobile Pentium 4 core, but with much better power-efficiency. Intel no longer recommends its Mobile Pentium 4 processors for mobile devices as they are outdated.

On July 27, 2006, Intel's Core 2 processors were released. By Q2 2007, Intel expected 90% of its laptop CPU production to be converted to the heavily-revised Intel Core 2 processors. The original Intel Core (Yonah) product had an unusually short lifespan as a stepping stone to the 64-bit Intel Core 2.