AN OVERVIEW OF PC MEMORY TYPES

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AN OVERVIEW OF PC MEMORY TYPES by Mind Map: AN OVERVIEW OF PC MEMORY TYPES

1. DYNAMIC RANDOM ACCESS MEMORY(DRAM)

1.1. Dynamic -because RAM needs always                  refreshing/updating to maintain                  information                -data in memory will                  disappears without                   refreshing

1.2. Random access-can put information anywhere                           on memory chip                          -any storage location can be                            accessed directly

1.3. unlike magnetic tape

2. SYNCHRONOUS DRAM(SDRAM)

2.1. SINGLE DATA RATE(SDR) -168 pins

2.2. DOUBLE DATA RATE(DDR) -twice data rate as ordinary SDRAM -same clock speed -184 pins

2.2.1. DDR-200 200 millions transfer per second ( must multiply by 8 to get throughput MB/S) 200 X 8 = 1,600 = PC1600 DDR-200 = PC1600

2.2.2. DDR 2 ~faster speeds-twice as fast as DDR                     -240 pins ~faster process ~not backwards compatible -DDR2 cannot work in DDR slots

2.2.3. DDR3 -twice fast than DDR2 -larger chip capacities -240 pins -no backwards compatibility -speed brings sacrifice

2.2.4. DDR,DDR2,DDR3 won't fit because it has no backward compatible

2.2.5. DIMM not able to put the wrong memory types into different memory slide

2.3. not a static RAM

2.4. memory synchronous with common system clock

2.5. 133 MHz clock=PC133

3. RAMBUS DRAM(RDRAM)

3.1. 400 MHz FSB Pentium

3.2. much faster

3.3. licensed by Rambus,Inc.

3.4. relatively expensive than SDRAM

4. RANDOM ACCESS MEMORY(RAM)

4.1. not only kind of memory

4.2. not hard disk/SSD storage

4.3. hard disk- data is stored permanently on the drive SSD storage- is a memory that stored data in long period of time

4.4. data and programs can only be used when moved to RAM -spreadsheat -word processing

5. READ ONLY MEMORY(ROM)

5.1. read information from memory

5.2. unable changed / erased the information inside memory

5.3. a great place for BIOS in computer

5.4. types: PROM- programmable ROM                      - engineer write once           EPROM- erasable PROM                       - can write/erase/write again                       - can making changes           EEPROM- electrically erasable PROM                         - has flash memory and SSD in computer                         - has upgrade BIOS for programmes

6. STATIC RAM(SRAM)

6.1. very fast memory

6.2. very expensive memory

6.3. very big memory

6.4. used often in processor caches -L1,L2,L3

6.5. do not have to refresh every time but still volatile