RAM (Random-access memory) is a form of computer data storage. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory. In contrast, with other direct-access data storage media such as hard disks, CD-RWs, DVD-RWs and the older drum memory,
The various memory formats:
- SIMM format memory modules (Single In-line Memory Module):
This type of memory was used with older systems: SIMM 30 connectors (8 bits) equipped the PC 286 and 386, and memory modules 72 connectors (32-bit) equipped the 386DX PC, 486 and first Pentium.
- format memory DIMMs (Dual In-line Memory Module):
This type of memory is currently used in our PC. These are 64-bit memories. Their dimension is 130x25mm. Unlike SIMM type memory, the DIMMs have memory chips from both sides of the bar.
- the size of memory modules SO-DIMM (Small Outline Dual In-line Memory Module):
This type of memory is currently used on our laptop. It is a compact DIMM.
The various types of memory:
- EDO DRAM (Extended Data Out)
This type of memory appeared in 1995. The main feature of this type of memory is its ability to address the next column while reading data from a column. The access time to memory EDO is 50 to 60 nanoseconds for a frequency range of 33-66 MHz. Not being capable of supporting frequencies above 66 MHz, this memory type has disappeared in favor of the SDRAM.
- SDRAM (Synchronous Dynamic RAM):
This type of memory appeared in 1997 to replace EDO memory. SDRAM allows, unlike the EDO memory, reading of data synchronized. It is capable of operating at frequencies up to 150 MHz with an access time of about 10 nanoseconds.
- DDR-SDRAM (Double Data Rate SDRAM):
This type of memory is based on technology SDRAM memory, which doubles the transfer rate of the SDRAM at the same frequency.
- DR-SDRAM (Rambus DRAM):
This type of memory is capable of operating at a frequency of 800 MHz, which gives it a bandwidth of 1.6 GB / s. This type of memory designed by Rambus and Intel corporations. This is a type of memory owner.
- DDR2-SDRAM (Double Data Rate two):
Second-generation DDR-SDRAM. His bus frequency is twice that of the memory cell group. A slot for DDR2-SDRAM (240-pin) can not support DDR-SDRAM (168 pins). In other words, DDR2 is not backward compatible with DDR (keyed differently positioned, not the same tension). Marketed from 2003.
Chips of different frequencies for different array of features DDR2:
PC2-3200 DDR2-400 chips the team strips clocked at 200 MHz bandwidth and 3.2 GB / s
PC2-4200 DDR2-533 chips the team strips clocked at 266 MHz bandwidth and 4.2 GB / s
PC2-5300 DDR2-667 chips the team strips clocked at 333 MHz bandwidth and 5.3 GB / s
PC2-6400 DDR2-800 chips the team strips clocked at 400 MHz bandwidth and 6.4 GB / s
PC2-8500 DDR2-1066 chips the team strips clocked at 533 MHz and bandwidth to 8.5GB / s
PC2-9600 DDR2-1200 chips the team strips clocked at 600 MHz bandwidth and 9.6 GB / s
- DDR3-SDRAM (Double Data Rate 3rd generation):
The third generation of DDR-SDRAM. It brings a number of improvements over the previous generation and offers better performance. Marketed from 2007.
Chips of different frequencies for different array of features DDR3:
PC3-6400 DDR3-800 chips the team strips clocked at 400 MHz bandwidth and 6.4 GB / s
PC3-8500 DDR3-1066 chips the team strips clocked at 533 MHz bandwidth and 8.53 GB / s
PC3-10600 DDR3-1333 chips the team strips 667-MHz bandwidth and 10.66 GB / s
PC3-12800 DDR3-1600 chips the team strips clocked at 800 MHz and bandwidth 12.8 GB / s
PC3-14400 DDR3-1800 chips the team strips clocked at 900 MHz and bandwidth 14.4 GB / s
PC3-16000 DDR3-2000 chips the team strips clocked at 1000 MHz and bandwidth 16.0 GB / s
PC3-17000 DDR3-2133 chips the team strips clocked at 1066 MHz and bandwidth 17.0 GB / s
What type of memory ram for my CPU?
- SDRAM: this type of memory exists in different frequencies (66, 100, 133 and 150 MHz). We use with Pentium 1, 2 and 3, the Intel Celeron, AMD K6 and Duron processors. The SDRAM 133 MHz are available in 128, 256 and 512 Mb.
- DDR-SDRAM: this type of memory exists in different actual frequencies from 100 MHz to 300 MHz. We use the Intel Pentium 4 and AMD Athlon processors.
- Rambus: This type of memory is used with the Intel Pentium 4
- DDR2-SDRAM: this memory type was used with processors out between 2004 and 2009
- DDR3-SDRAM: this type of memory used with processors out since 2008