MEMORY TECHNOLOGY MEMORY TECHNOLOGY FOR SMALL FORM FOR SMALL FORM FACTOR SYSTEMSFACTOR SYSTEMS

Bill Gervasi

Chairman, JEDEC Memory Parametrics

Market ChangesMarket Changes

• Desktop PC getting smaller and smallerFlex/ATX form factorTiny sealed box legacy free PCs

• Server market shifts to 1U form factorPacking more CPUs into a smaller frameHeat dissipation a top concern

• Performance ramping higher and higher

• System (fan) noise concerns

New System DesignsNew System Designsand Form Factorsand Form Factors

Combine market segmentsCombine market segments

DIMM SO-DIMM MicroDIMM

High capacity server, “4U”, Workstation

Desktop, Notebook,

“1U”, Router, Blades

Subnotebook, PDA

64MB – 2GB per slot

64-256 MB per slot

32-256 MB per slot

It’s Time for a ChangeIt’s Time for a Change

• PC demand plateau at 128-256 MBDDR SO-DIMM clearly meets this need

• 30% of FlexATX PCB is memory sockets & traces

• 1U = 86% of server market (by unit)Trying to fit 6-8 CPUs in one 19” rack

• Increasing operating frequency harder to achieve with 5¼“ DIMM

Comparing DDR Memory Comparing DDR Memory ModulesModules

DDR ModulesDDR Modules

SO-DIMM

DIMM

NEW!MicroDIMM

SO- and Micro- DIMMsSO- and Micro- DIMMs

DDR SO-DIMM = 67.6 mm

= 50% shorter!

DDR MicroDIMM = 45.5 mm

= 66% shorter!!!

DDR DIMM = 133.3 mm

North Bridge

Copper

Slots

FlexATX FootprintFlexATX Footprint

With DIMM:

17k mm2

With SO-DIMM:

7k mm2Area saved

~ 60%

Server MarketServer Market

86%

10%

4%

Edge (86)Apps (10)Database (4)

1U form factor or blade600 MHz x86 CPU256MB – 1GB RAM

(by unit shipment; source = Intel)

1U Thin and 3U Blades1U Thin and 3U Blades

1U

3U

Vertical Socket Right Angle Socket

Operating FrequencyOperating Frequency

DIMM

4,8,9,16,18,36 chips

x4, x8, x16 devices

Unbuffered or Registered

SO-DIMM

4,5,8 chips

x8, x16 devices

Unbuffered Only

MicroDIMM

4,8 chips

x16 devices

Unbuffered Only

Which do you think will run the fastest?Which do you think will run the fastest?

Matching Requirements Matching Requirements and Implementationsand Implementations

SO-DIMM RequirementsSO-DIMM Requirements

• Low cost vertical socket neededSmallest PCB footprintEnable 4 layer motherboard

• Socket concepts in progressStaggered surface mountSingle routing layer possible!

• Right angle socket okay for blade

Concept Under AnalysisConcept Under Analysis

Discussions Under WayDiscussions Under Way

Began negotiations with the major mother board manufacturers – all are

open to evaluating the concept

Of course, no one will make the move unless

WE ALL MOVE TOGETHER

Fire StartedFire Started

• One major embedded application on the hookProduction of 250 Ku/mo beginning 1Q02Enough to kick start the program

• Task group formedConference calls to gather requirementsSocket suppliers debating implementation

& cost details

We have an opportunity to establish the We have an opportunity to establish the DDR SO-DIMM as the highest volume, DDR SO-DIMM as the highest volume,

lowest cost, highest performance lowest cost, highest performance memory module in the industry.memory module in the industry.

What about MicroDIMM?What about MicroDIMM?

• Notebooks & subnotebooks

• PDAs and Web Tablets

• High density 1U servers???

High Density 1UHigh Density 1U

Inte

rcon

nect

fa

bric

and

I/O

CPU

CPU

CPU

CPU

CPU

CPU

CPU

CPU

Mem

Mem

Mem

Mem Mem

Mem

Mem

Mem

MicroDIMM RequirementsMicroDIMM Requirements

• DDR MicroDIMM used in high density 1URight angle socket okay… 1x2” footprintOne module per CPU

• No vertical socket demand seen… yet…

Heat & NoiseHeat & Noise

Dealing w/ heat and noiseDealing w/ heat and noise

• Greatest challenge for 1U server is HEAT

• Dissipating heat takes FANS

• Fans generate MORE HEAT

Fanless Desktop PC?Fanless Desktop PC?

• What doesn’t fit?MP3 music100W per channel ampBose surround sound speaker systemPC fans with 75 dB of white noise

Power: DDR vs SDRPower: DDR vs SDR

0

0.5

1

1.5

2

Relative Watts

PC100

(3.3V)

1.2X

DDR266

(2.5V)

1.0X

PC133

(3.3V)

2.0X

Lower Voltage means

Lower Power

Power: DDR vs SDRPower: DDR vs SDR

0

0.2

0.4

0.6

0.8

1

Relative MB/s per Watt

PC100

.31X

DDR266

1.0X

PC133

.25X

Double the Bandwidth yet Lower Power

DDR Reduces PowerDDR Reduces Power

• Using DDR for main memory helps control system power

• Lower power reduces or eliminates need for fans

Bold ProjectionBold Projection

• Fanless desktop PCs for home and small office will become a significant market demand

• DDR will help enable this important market segment

Another Wild CardAnother Wild Card

• Low Power SDR1.8VNo DLL Inventive refresh options

• Some focus here, especially for cell phones… will it spread?

• Features considered for DDR family, too

Cached DRAM Power ProfileCached DRAM Power Profile

NOP ACT R-PRE R R NOP

NOP R R R R NOPLower Power

Higher Power

Command Activity

Page Miss Power Profile

Page Hit Power Profile

Command Activity

…

…

ConclusionsConclusions

• Market form factors are changing

• New designs require rethinking our past assumptions

• DDR SO-DIMM could replace the DIMM for desktop applications

• Lower power would allow us to eliminate noisy fans

Thank YouThank You