RAM on the Motherboard Loses all data when PC is turned
off (except data stored on CMOS chip)
Two categories– Static RAM (SRAM)
Fast Used as a memory cache
– Dynamic RAM (DRAM) Slower; requires constant refreshing
DRAM
SIMM technologies– Can use either EDO or FPM
technology
DIMM technologies– Can use either BEDO (burst EDO) or
synchronous RAM (SDRAM)
RIMM technologies– Each socket must be filled to
maintain continuity
Upgrading Memory
What to look for when buying memory chips and modules
How much and what kind of memory to buy
Reading ads about memory modules
Installing memory
What to Look for When Buying Memory Chips and Modules Use type, size, density, and
fastest speed supported by the motherboard
Match tin leads to tin connectors and gold leads to gold connectors
Beware of remanufactured and re-marked memory chips
How Much and What Kind of Memory to Buy Determine how much memory
you have and need
Identify the number, type, and size of memory modules supported by your motherboard
Determine how much memory can you afford
Match memory modules to the motherboard
Installing Memory
Protect chips against static electricity
Usually modules pop into place easily and are secured by spring catches on both ends
Types of RAM
SDRAM– Systems use some form of
synchronous DRAM (SDRAM) Still DRAM, but it is synchronous
– SDRAM DIMMs came in a wide variety of pin sizes
Desktops were the 168-pin variety. Laptop DIMMs came in 68-pin, 144-pin
RDRAM
Replace SDRAM with a very fast, new type of RAM developed byRambus, Inc. called Rambus DRAM, or simply RDRAM
Came in two sizes: – A 184-pin for desktops – A 160-pin SO-RIMM for laptops
DDR SDRAM
Double Data Rate SDRAM (DDR SDRAM)
DDR SDRAM for desktops comes in 184-pin DIMMs
DDR SDRAM for laptopscomes in either 200-pin SO-DIMMs or 172-pin micro-DIMMs
DDR2
Run at a blistering PC4800. 4.8 gigabytes per second (GBps)
of data throughput DDR2 uses a 240-pin DIMM that’s
not compatible with DDR