CompactPCI and AdvancedTCA Systems - OpenSystems Media

SPECIAL7447A processors at different clock ratesusing message sizes of 48 KB.With a total of five Gigabit Ethernet interfaces,the card is capable of well in excessof 300 MBps throughput. A system comprisedof many CAV4s would have dramaticallymore Ethernet communicationsbandwidth than that provided by a singlePCIbus.Power consumptionIt is a well-known phenomenon that thepower consumption of microprocessorsand accompanying system logic has beensteadily rising. Desktop processors fromIntel and AMD now top 100 W. In highperformancemultiprocessor computingapplications, the name of the game howeveris computing density. The questionis, “How much real computing work canbe accomplished within the confines ofstandard enclosures and racking systems,without resorting to prohibitively expensivecooling technologies such as spraycooling or refrigerated air systems?”The latest generation of quad processordesigns is starting to push the envelopeof available cooling in the IEEE 1101.10mechanical standard. A precision airmass-flow measurement test was developedby Curtiss-Wright to qualify andaccurately specify the cooling requirementsfor high-power, air-cooled processorboards. In concert with this program,we have characterized the power consumptionof the Compact CHAMP-AV IVat different processor clock rates and inletair-temperatures. Table 2 shows the powerfor a test scenario designed to stress theprocessors and memory subsystem of thecard, thereby consuming power in excessof the majority of real applications.These tests highlight some of the factorsthat influence power consumption. Fasterclock rates are usually accompanied withthe need to power the processor core athigher voltage, causing relatively largeincreases in power for relatively modestincreases in clock rates between 998 MHzand 1064 MHz. The other factor that isperhaps less well understood is processors’drawing more power when runningat higher silicon die temperatures,illustrating the need for effective thermaldesigns and air-management within theenclosure. Freescale’s power estimatesfor the 7448 processor are not publiclydisclosed, but we expect to see powerreductions at equivalent test conditions.Much of the technology required forapplications with high performance needsin the military market such as radar,sonar, and signal intelligence can beapplied in products aimed at the high-endof the commercial/industrial CompactPCImarket space where performance andpackaging density is valued but extremeruggedization is not.Ian Stalker is the DSP productmanager for Curtiss-Wright ControlsEmbedded Computing. He holds morethan 20 years of experience in theembedded industry and has a degreein Electronic Engineering.For further information, contact Ian at:Curtiss-Wright ControlsEmbedded Computing741-G Miller Drive, SELeesburg, VA 20175Tel: 703-779-7800 • Fax: 703-779-7805E-mail: ian.stalker@curtisswright.comWebsite: www.cwcembedded.comProcessor ClockEthernet Performance665 MHz 62.6 MBps998 MHz 79.1 MBps1064 MHz 79.1 MBpsTable 1Core Voltage 1.0 V 1.0 V 1.1 VCore Frequency 665 MHz 998 MHz 1064 MHzAverage Power@ 25 °C inlet47.6 W 54.7 W 64.9 WAverage Power@ 50 °C inlet50.6 W* 59.2 W 70.9 W*Power measured at 40 °C for this test.Table 2RSC# 23 @www.compactpci-systems.com/rsc