July 27, 2009

Editor: Tom R. Halfhill

In this issue:

• Hot-Rodding the Cortex-A8

Hot-Rodding the Cortex-A8

ARM’s fastest microprocessor core keeps getting faster. Only five months ago, Texas Instruments announced a 1.0GHz ARM Cortex-A8 in future OMAP3 cellphone chips. Now Intrinsity is unveiling a 1.0GHz Cortex-A8 accelerated with dynamic logic. Intrinsity’s new core, code-named Hummingbird, is functionally identical to a Cortex-A8 implemented in standard-cell static logic.

Intrinsity says Hummingbird can reach 1.0GHz under worst-case conditions at 1.2V when fabricated in a 45nm-LP low-leakage process. It could exceed that clock frequency in a faster but leakier 45nm-GP generic process. Throughput at 1.0GHz is 2,000 native mips.

According to Intrinsity, power consumption is very low for a processor with this performance. Unfortunately, Intrinsity’s lead customer—Samsung Electronics—isn’t publicly disclosing power measurements at this time. Microprocessor Report estimates that active power at 1.0GHz is less than 750mW, with static leakage in the very low milliwatt range. Low leakage is particularly important for battery-powered mobile systems with intermittent usage patterns, such as cellphones.

Note that Samsung makes the application processor in the hot-selling Apple iPhone 3GS. Previous iPhones had an ARM11-based Samsung SoC running at 412MHz, but the iPhone 3GS has a Cortex-A8 running at 600MHz. In theory, Samsung could drop Intrinsity’s 1.0GHz Hummingbird into the existing design with few or no changes, boosting throughput by 67% without busting the iPhone’s power budget.

Graphics with this article:

Table 1. Estimated Cortex-A8 performance in different implementations and fabrication processes.
Figure 1. Intrinsity Fast14 design flow.


Microprocessor Report readers can access the full story (5 pages) here: www.mdronline.com/mpr/h/2009/0727/233001.html.

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