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DDR SDRAM The Memory of Choice for Mobile Computing

DDR SDRAM The Memory of Choice for Mobile Computing. Bill Gervasi Technology Analyst, Transmeta Corporation Chairman, JEDEC Memory Parametrics bilge@transmeta.com. Topics to Cover. Market Segments & Fragments Mobile Design Architectures DDR and SDR Power Analysis DDR SO-DIMM Details.

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DDR SDRAM The Memory of Choice for Mobile Computing

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  1. DDR SDRAMThe Memory of Choicefor Mobile Computing Bill Gervasi Technology Analyst, Transmeta Corporation Chairman, JEDEC Memory Parametrics bilge@transmeta.com

  2. Topics to Cover • Market Segments & Fragments • Mobile Design Architectures • DDR and SDR Power Analysis • DDR SO-DIMM Details

  3. Segments & Fragments Servers Workstations PC Segment 2 PC Segment 1 PC Segment 0 Mobile Graphics DDR PC100 PC133 PC100 PC133 DDR Rambus PC100 DDR PC100 PC133 DDR PC100 DDR PC133 PC66 PC100 DDR PC133 DDR (x16 and x32) SS167 2H99 1H00 2H00 1H01 2H01

  4. RAM Evolution 3200MB/s MainstreamMemories DDR II 2100MB/s DDR 1000MB/s SDR 400MB/s Simple,incrementalsteps 320MB/s EDO FP

  5. Mobile Designs Mobile Memory Controller • Two Sockets, T-stub • 133MHz clock (for now) • 2.1GB/s transfer (for now)

  6. Butterfly SO-DIMMs Motherboard • Perfect for notebook • Especially thin & light! • Single access door to both SO-DIMMs • Internet Appliance: 1 or 2 SO-DIMMs SO-DIMM SOCKET CPU CPUNB SO-DIMM SOCKET

  7. Mobile Market Requirements • Low power, low heat • Long battery life • Small form factor • End-user upgrade

  8. Power = CV2f% Keys to mobile design: • Reduce C and V • Match f to demand • Minimize duty cycle • Utilize power states Factors: • Capacitance (C) • Voltage (V) • Frequency (f) • Duty cycle (%) • Power states

  9. Power: Capacitance Capacitance Voltage Frequency Duty cycle Power states • DDR capacitance 20% less than SDR • Tight circuit board design • Low parasitic sockets

  10. Power: DDR vs SDR Capacitance Voltage Frequency Duty cycle Power states Lower Voltage meansLower Power PC133 (3.3V) 2.0X PC100 (3.3V) 1.2X PC266 (2.5V) 1.0X

  11. Power: DDR vs SDR Capacitance Voltage Frequency Duty cycle Power states Double the Bandwidth yet Lower Power PC266 1.0X PC100 .31X PC133 .25X

  12. Power: Frequency Capacitance Voltage Frequency Duty cycle Power states • Memory speed to match task demand • Adjust memory clock for lowest power • Stream back to back operations on open bank, then close • DDR burst efficiency really shines

  13. Power: Duty Cycle Capacitance Voltage Frequency Duty cycle Power states • Caches minimize memory demands • DDR cuts burst time in half • Get back into low power state sooner

  14. Long Battery Life • Lowest power to perform a task • Desktop performance expected • Battery extending technologies: • SpeedStepTM • LongRunTM SpeedStep and LongRun are trademarks of Intel Corporationand Transmeta Corporation, respectively

  15. Introducing LongRunTM Capacitance Voltage Frequency Duty cycle Power states SpeedStep LongRun The number 11 is a trademark of Spinal Tap

  16. LongRunTM Technology Capacitance Voltage Frequency Duty cycle Power states • Smart reprogramming of memory frequency based on demand • CPU monitors trends in CPU demand • Automatically adjust CPU voltage,CPU & memory frequency as needed • Utilize all memory power states • Lowest power state possible • Close banks between bursts LongRun is a trademark of Transmeta Corporation

  17. LongRunTM Advantage Capacitance Voltage Frequency Duty cycle Power states

  18. Mobile Market Requirements • Long battery life • Low power, low heat • Small form factor • End-user upgrade

  19. End User Upgrade • DDR SO-DIMM Status • 63.6 x 31.75mm • 200 pins on .60mm centers, staggered • x64 and x72 (ECC) supported • JEDEC specification votes being counted • Multiple mobile designs in progress • Samples in test now, production 1Q01 • Also great for small (Flex ATX) desktop

  20. Conclusions DDR • Memory of choice for the future • Enables mobile computing • Low power yields long battery life • Small form factor end-user upgrades • Smart power management schemes

  21. Summary • DDR is here today • Double the bandwidth at lower power • Evolutionary design change over SDR • Applies to all market segments • Industry Standards • Detailed complete data sheet & models • Module designs on the web • Visit http://www.ami2.org

  22. Thank You

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