DDR SDRAM The Memory of Choice for Mobile
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 n Market Segments & Fragments n Mobile Design Architectures n DDR and SDR Power Analysis n DDR SO-DIMM Details 2
Segments & Fragments Servers PC 100 PC 133 DDR Workstations PC 100 PC 133 DDR PC Segment 2 PC Segment 1 PC Segment 0 Mobile Graphics Rambus PC 100 PC 133 PC 100 PC 66 DDR PC 133 PC 100 PC 133 DDR DDR (x 16 and x 32) SS 167 2 H 99 1 H 00 2 H 00 1 H 01 2 H 01 3
RAM Evolution 3200 MB/s Mainstream Memories R DD 2100 MB/s 1000 MB/s R D S 400 MB/s 320 MB/s O D E FP 4 II R D D Simple, incremental steps
Mobile Designs Mobile Memory Controller n Two Sockets, T-stub n 133 MHz clock (for now) n 2. 1 GB/s transfer (for now) 5
Butterfly SO-DIMMs Motherboard CPU SO-DIMM CPU NB SO-DIMM n SOCKET Perfect for notebook m Especially thin & light! Single access door to both SO-DIMMs n Internet Appliance: 1 or 2 SO-DIMMs n 6 SOCKET
Mobile Market Requirements u Low power, low heat u Long battery life u Small form factor u End-user upgrade 7
Power = CV 2 f% Keys to mobile design: Factors: n Capacitance (C) n Voltage (V) n Frequency (f) n Duty cycle (%) n Power states n n 8 Reduce C and V Match f to demand Minimize duty cycle Utilize power states
Power: Capacitance Voltage Frequency Duty cycle Power states n DDR capacitance 20% less than SDR n Tight circuit board design n Low parasitic sockets 9
Power: DDR vs SDR Lower Voltage means Lower PC 133 (3. 3 V) 2. 0 X PC 100 (3. 3 V) PC 266 1. 2 X (2. 5 V) 1. 0 X 10 Capacitance Voltage Frequency Duty cycle Power states
Power: DDR vs SDR Double the Bandwidth yet Lower PC 100. 31 X PC 266 1. 0 X PC 133. 25 X 11 Capacitance Voltage Frequency Duty cycle Power states
Power: Frequency Capacitance Voltage Frequency Duty cycle Power states n Memory speed to match task demand m Adjust memory clock for lowest power n Stream back to back operations on open bank, then close m DDR burst efficiency really shines 12
Power: Duty Cycle Capacitance Voltage Frequency Duty cycle Power states n Caches minimize memory demands n DDR cuts burst time in half n Get back into low power state sooner 13
Long Battery Life n Lowest power to perform a task n Desktop performance expected n Battery extending technologies: m Speed. Step. TM m Long. Run. TM Speed. Step and Long. Run are trademarks of Intel Corporation and Transmeta Corporation, respectively 14
Introducing Long. Run. TM Speed. Step Capacitance Voltage Frequency Duty cycle Power states Long. Run The number 11 is a trademark of Spinal Tap 15
Long. Run. TM Technology Capacitance Voltage Frequency Duty cycle Power states n Smart reprogramming of memory frequency based on demand m CPU monitors trends in CPU demand m Automatically adjust CPU voltage, CPU & memory frequency as needed n Utilize all memory power states m Lowest power state possible m Close banks between bursts Long. Run is a trademark of Transmeta Corporation 16
Long. Run. TM Advantage 17 Capacitance Voltage Frequency Duty cycle Power states
Mobile Market Requirements n Long battery life n Low power, low heat n Small form factor u End-user upgrade 18
End User Upgrade n DDR SO-DIMM Status m 63. 6 x 31. 75 mm m 200 pins on. 60 mm centers, staggered m x 64 and x 72 (ECC) supported m JEDEC specification votes being counted n Multiple mobile designs in progress n Samples in test now, production 1 Q 01 n Also great for small (Flex ATX) desktop 19
Conclusions n Memory of choice for the future n Enables mobile computing m Low power yields long battery life m Small form factor end-user upgrades n Smart power management schemes 20
Summary n DDR is here today m Double the bandwidth at lower power m Evolutionary design change over SDR m Applies to all market segments n Industry Standards m Detailed complete data sheet & models m Module designs on the web m Visit http: //www. ami 2. org 21
Thank You 22
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