AMD’s Quad-Core Chips to Feature Advanced Power Saving Techniques

by Anton Shilov
02/12/2007 | 01:58 PM

Advanced Micro Devices, the No. 2 maker of x86 microprocessors, continues to unveil details about its forthcoming code-named K8L chips for various applications and quad-core chips for servers. During a presentation to the International Solid State Circuits Conference (ISSCC) AMD unveiled some of the technologies that are set to reduce power consumption of the new chips.

Earlier it was indicated that improvements of AMD PowerNow! technology will enable systems based on native quad-core AMD Opteron processors to dynamically adjust frequencies at the individual core level for further power consumption reductions.

In addition, the new K8L processors will be able to change voltages of different partitions of the chip individually as well: for example, it will be possible to reduce processing engines’ voltage independently from memory controller. This enables the memory controller to service external memory requests independent from core p-state transitions, thus enabling p-state opportunities which can lead to additional power savings.

Additionally, the system memory interface of K8L also includes a feature that powers down memory logic when not in use.

AMD has also made extensive use of “clock gating” in the “Barcelona” design to enable automatic shut-down of areas of logic not being utilized for further power savings.

As previously reported, AMD’s code-named Barcelona processors for servers produced using 65nm process technology and featuring a broad range of functionality and micro-architectural improvements will be drop-in compatible with socket 1207 (socket F) infrastructure and will be commercially available in mid-2007.

“Today’s IT system purchasers must weigh performance-per-watt as well as raw performance as they make their buying decisions,” noted Nathan Brookwood, Research Fellow at Insight 64. “By doubling the number of cores, adding a shared third level cache and applying a variety of other extensive CPU design enhancements, AMD’s ‘Barcelona’ designers clearly have addressed the numerator in the performance-per-watt equation. Today’s ISSCC disclosures reveal ‘Barcelona’ also includes innovations such as the ability to vary each CPU core’s frequency independently, along with a number of proven energy-saving techniques like ‘clock-gating’ that address the denominator in the equation. The combination of these new performance and power-saving features should drive a dramatic improvement in the already strong performance-per-watt AMD Opteron processor-based systems offer today.”