RAM Technology

Presented By

Courtney WhiteNaomi Bristol

Mark PellegriniOscar King’ara

RAM Technology

• RAM Basics• Types of RAM• Marketplace Conditions• The Future of RAM

RAM Basics

RAM Basics• What is RAM?• DRAM

-Dynamic Random Access Memory-paired capacitor and transistor per bit-requires refreshing of charged capacitors-physical memory

• SRAM-Static Random Access Memory-four to six transistors per bit (flip-flops)-does NOT require refreshing…faster than DRAM-bigger and more expensive than DRAM-cache

• PRAM-Apple Macintosh’s RAM

• FLASH RAM-low power RAM

RAM Basics• Memory Controller

-Error checking-NOT error correction code (ECC)

• Form Factors-SIMM (Single In-line Memory Module)

- 30-pin or 72-pin

- 8MB to 256MB

-DIMM (Dual In-line Memory Module)- 168-pin

- 32MB to 1GB

-SODIMM (Small Outline Dual In-line Memory Module)

-RIMM (Rambus In-line Memory Module)-184-pin-64MB to 1GB

Types Of RAM

Types of RAM

• PMDRAM– Page Mode Dynamic

Random Access Memory

– Original form of DRAM

– Very slow type of RAM

• FPMDRAM– Fast Page Mode

Dynamic Random Access Memory

– Big improvement over PMDRAM

– More efficient data access

Types of RAM

• EDO DRAM– Extended Data-Out

Dynamic Random Access Memory

– Faster access of data– Approximately 5%

faster than FPMDRAM

• BEDO DRAM– Burst Extended Data-

Out Dynamic Random Access Memory

– Incorporates “burst” method

Types of RAM

• SDRAM– Synchronous Dynamic

Random Access Memory

– Synchronized with CPU

– Advantages in accessing data compared to predecessors

• DDRDRAM– Double Data-Rate

Dynamic Random Access Memory

– Similarity with SDRAM with major improvement

Types of RAM

• RDRAM– Rambus Dynamic

Random Access Memory

– Rambus Inline Memory Module

– 800 MHZ data rate– Has double data rate

• VRAM– Video Random Access

Memory– Multiport Dynamic

Random Access Memory (MPDRAM)

– Typical Uses– Color and Resolution

Types of RAM

• PCMCIA– Personal Computer Memory Card International– Designed for attaching input/output devices

Marketplace Conditions

The RAM Environment

Nathan’s First Law : “Software is a gas; it expands to fill its container ”(Nathan Myhrvold)

Moore’s Law and RAM

Major Players• Processor Companies

– Intel

– AMD

• Chipset Designers

– KT

– Via

– SiS

• RAM Manufacturers

– Samsung,

– Corsair

– Twinmos

– Many others (generic Taiwanese companies)

Note: Apple is different in that they manufacture their RAM. Mac desktops are limited to 8 or 10ns (depending on model) 168-pin SDRAM, bus speeds vary. Production is outsourced to the same generic Taiwanese companies that do PC architecture.

A Brief History286, 386 and early 486 30 pin SIMM (70ns)

[80ns for 286 and early 386]

Late 486 (over 50MHz) 72 pin SIMM

Early Pentium (Up to 90 MHz) DIMM (SDRAM) (133 MHz)

Pentium, Pentium MMX, Pentium Pro, 72 pin DIMM EDO,Pentium II, BX series motherboards 168 pin DRAM

168 pin SDRAM

Pentium III Motherboards100/133 Mhz DIMM (SDRAM) (133 MHz)

Pentium IV Motherboards RIMM (RDRAM) (Up to 400 MHz)

Source - University of Melbourne - http://www.its.unimelb.edu.au/ucs/pricelist/ramguide-text/intel/

Recent Developments in the Field - 1

Rambus Hurting, DDR FlourishingAmong the experts, DDR SDRAM

technology is considered to be the one that is the most promising and has the

most possibility for further development…Still, there are problems regarding limited bandwidth, and above all the latency...DDR SDRAM is a logical

continuation developed from DRAM technology, but it is by no means the

final word. Also, the connection from the memory module to the chipset is critical. Only an optimized memory interface of

the chipset allows for maximum performance with DDR modules.

--Tom’s Hardware, May 2002

http://www17.tomshardware.com/mainboard/02q2/020501/ddr400vsrambus-02.html

In August, Intel announced that they will be dropping Rambus in favor of DDR

DDR-400 Premiers

Recent Developments in the Field - 2

Samsung announced in July that they had developed (in conjunction with SiS, Via, and nVidia) the first DDR-400 RAM.Source: “Samsung Collaborates with NVIDIA, SiS and VIA to Bring DDR400 To Market”, http://www.semiseeknews.com/press_release4045.htm

Tom’s Hardware reviewed it, but the tests showed it to be only marginally better than its predecessor. Source: “DDR Kills Rambus”, Tom’s Hardware http://www4.tomshardware.com/mainboard/02q3/020720/index.html

Limiting Factors• Chipset

– Intel• Intel 845G

• Intel E7205 (Under fire)• Via4X333• SiS-648

– Athlon• Kt400

• Front Size Bus

The Future of RAM

QBM Technology

• Quad Band Memory (QBM) technology• Currently 3 types of memory technology

readily available and incorporated into the design of mainboards: PC133, DDR, Rambus

• The key is that QBM doubles the amount of data packed into each address line

Taken from http://www.kentrontech.com/Kentron

_Products/QBM_availability.htm

Part of the magic of QBM is that it does not require any change to the DRAM. It is a platform (or module) based technology that uses standard off-the-shelf components including the standard, existing DDR devices. To ensure backwards compatibility with DDR modules at the system level, QBM was designed with the standard 184-pin DIMM outline. The module width is eight Bytes and supports ECC.

Taken from http://www.viaarena.com/?PageID=1

80

Further to these benefits, QBM technology eliminates the bottleneck found in today's Pentium 4 platform systems.

DDR333 and DDR400 modules cannot transfer data as quickly as the Pentium 4 processor can execute transactions.

Taken from http://www.viaarena.com/?PageID=1

80

By scaling the memory clock and FSB frequencies to run synchronous, QBM technology eliminates the bandwidth gap.

MRAM

• Magnetic or magnetoresistive random access memory

• “instant-on” computing in the same way you turn on your television – all information immediately available

• Uses magnetism to store data – retains its state when the power is removed

MRAM (cont…)

• touted to be the next revolutionary memory technology that can potentially replace DRAM, SRAM and Flash with advantages like non-volatility, unlimited read and write endurance, fast access, and low power

MRAM

• Opportunities include:non-volatile storage of critical boot data to achieve instant-on computingportable systems w/ less power consumption, extending the battery lifeability to retain the OS, your data, and even applications in the event of a crash

MRAM: Time Outlook

• MRAM technology has taken nearly 30 yrs to develop

• IBM successfully built a working MRAM chip in 1998; now the challenge is to produce a chip that can store large amts of data and be made for an affordable cost to consumers

• By 2003, IBM and Infeon expect to have test chips in use

• If successful, transition to MRAM is expected to be in full swing around 2004

Holographic Memory• Stackable storage -

stacks information throughout the thickness of a storage medium, instead of just writing it to the surface

Holographic Memory: Implications

• Able to store more information in a smaller space and offer faster data transfer times –possibility of storing 1 terabyte of data in a sugar-sized crystal ~ 200 DVDs

• possibility of reading and writing data a million bits at a time, instead of one by one as with magnetic storage -- duplicate an entire DVD movie in mere seconds

Holographic Memory: Time Outlook

• First proposed by Polaroid scientist Pieter van Heerden in the early 1960s

• After more than 30 yrs of R&D, IBM has suggested a small desktop holographic storage system (HDSS) device may be ready as early as 2003, with capacities of 125 GB and transfer rates of ~40MB/sec

Ferroelectric RAM (FRAM)

• Being pushed by Texas Instruments as replacement for embedded flash and embedded DRAM

• Has similar structure to DRAM but w/ a layer of electrically polarizable material as storage element, providing non-volatile storage

FRAM: Time Outlook

• Vice-president of R&D at TI would like to be in production in 2005