| Moore's
Law states that processing power will double every 18 months. And
since the introduction of the Intel 8088 processor, this law has
never been broken. But increasing the performance of a processor
also requires increasing the bandwidth of the memory subsystem.
Here's a brief look at the past, present, and future memory
technologies . Fast Page - The standard type of memory for 486, and early
Pentium 60/66/75/90 (still remember those?) systems. Back then, fast
page memory was sufficient to keep up with the processor.
- EDO - Extended Data Output. EDO delivers about 10%-15%
performance increase from fast page memory. The read cycle from
memory and CPU is shorten. EDO became the dominant memory when
the Pentium 100/133/150/166 (non-MMX) appeared on the market.
- SDRAM - Synchronous DRAM. With the advent of the
Pentium MMX and Pentium II processors, memory technology took
another leap in terms of raw speed. SDRAM coordinates the input
and output of the memory and the processor. Makers of SDRAM
claim a performance improvement of 50% or more over EDO memory.
But in the real world, the performance is only about 20%.
Currently, SDRAM is the dominant memory type, for both the 66MHz
and the new 100MHz (PC100) bus.
- SDRAM II (DDR) - Double-data rate SDRAM aims to double
the performance of current SDRAM. DDR allows the processor to
read from memory on both the rising and falling edge of the
clock. Currently, no Intel or third party chipset fully supports
DDR.
- RDRAM - Rambus DRAM. This is based on the technology
developed by Rambus, Inc.
Intel have selected RDRAM for their future processors, IA-32 (Katmai)
and beyond. RDRAM uses a narrow data channel clocked at
extremely high speed to achieve high performance. The Nintendo
64 game console uses Rambus as its primarily memory interface.
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