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Building & Buying a PC

Volume I, Issue No.7 JULY12, 1995

-Extended Data Out Random Access Memory-EDO RAM-

Increase performance over standard DRAM by 20%.

EDO RAM, a type of DRAM which supports a "fast paging mode",allowing for faster access. EDO RAM is primarily used with Intel'sPentium processors and Intel's "Triton" chipset(see chipset below). In early 1995, EDO RAM was availablefor computers from Micron, Gateway, and Intel.

chip set

A collection of integrated circuits that are designed to be usedtogether for some specific purpose. Eg. control circuitry in anIBM PC.

Burst EDO DRAMs: The performance option worth watching!

Designed for a new level of performance without paying the price.

Burst Extended Data-out (EDO) is a cost effective, high-speedaccess option to standard DRAMs that can increase the page moderate to 66 MHz bus speeds- without requiring changes to systemarchitecture. They use standard DRAM packaging and need only minortiming modifications.

The concept behind the Burst EDO memory is to carry the EDO DRAM,in its existing package, to a higher performance level. EDO isa simple modification to a Fast Page Mode (FPM) DRAM that allowsthe EDO Page Mode rate to be improved from 25 MHz up to 50 MHz.Burst EDO is a further improvement to EDO that increases the pagemode rate to 66 MHz and beyond. This speed increase is achievedby implementing a processor-compatible, four-cycle burst counton-chip.

A key advantage of Burst EDO over more complicated high-speedDRAM alternatives is the ease of implementation. Burst EDO DRAMsuse packages and pinouts identical to standard EDO DRAMs. Newbus architecture, a separate die, or dedicated test and productionequipment are not necessary. Chipset vendors will make only minimalchanges to their designs to support Burst EDO.

Highlights of the new Burst EDO...

Zero wait state bursts at 66 MHz

Multiple DRAM vendor support

Multiple chipset support

Same pinout and package as EDO DRAMs

Cost effective performance - on the same die as industry standardFPM DRAMs and high volume EDO DRAMs

3.3V operation with 5V tolerant I/O for 5V system or 3.3V systemoperation

Supports both Intel burst order and linear burst order

Available on industry standard modules: 72-pin SlMM (FPM or EDO)and 168 pin DIMM (FPM or EDO)

Pentium Chipsets Supporting EDO DRAMs

Currently available Chipsets

Intel Triton, OPTI Viper, VLSI Wildcat chipsets.

Other Chipsets will be made available shortly.

Expect 486 CPU support very soon!

Sources: Intel & Micron Technology

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