What is RAM and what does it do?

RAM - Random Access Memory, or volatile memory, is used by the system to store data for processing by a computer's central processing unit (CPU), also known as the processor. RAM stores the data in memory cells that are arranged in grids much like the cells are arranged in a spreadsheet, from which data, in the binary form of 1's and 0's, can be accessed and transferred at random to the processor for processing by the system's software.

The data stored in a hard disk drive (HDD) cannot be accessed at random. Whole sectors, containing blocks of data, are transferred from a hard disk drive, placed in a large swap file on the same drive, and only then are selected files transferred to RAM for random access by the processor, which is itself only performing the instructions of the system's operating system (usually Windows), and its application software.  

Whenthe computer is turned off, all of the data in the RAM memory is lost, hence its alternative name of volatile memory, whereas all of the data on a hard disk drive is retained permanently until it is intentionally erased. The motherboard (or mainboard) manual (that should be provided with a new or a second-hand PC) will provide all of the details about the different types of supported RAM, and the various combinations of modules per bank for each type that can be successfully installed.

You can use some of the easy tools to find your exact DDR or DDR2 Memory Upgrades for your Desktop, Laptop or Servers.
Use the Memory Selector to find compatible DDR or DDR2 Memory Upgrades, or the all new system scanner tool to scan your system to find exact matching DDR RAM. If you need more help use the Live Chat Support

DDR Memory Upgrades | DDR2 Memory Upgrades

DDR Memory RAM
PC2100 266Mhz Memory DIMM | PC2700 333Mhz DDR Memory DIMM | PC3200 400Mhz DDR Memory DIMM
PC2100 266Mhz DDR SODMM | PC2700 333Mhz DDR SODMM | PC3200 400Mhz DDR SODMM


DDR SDRAM for desktop computers DIMMs have 184 pins (as opposed to 168 pins on SDRAM, or 240 pins on DDR2 SDRAM), and can be differentiated from SDRAM DIMMs by the number of notches (DDR SDRAM has one, SDRAM has two). DDR for notebook computers SO-DIMMs have 200 pins which is the same number of pins as DDR2 SO-DIMMs. These two specifications are notched very similarly and care must be taken during insertion when you are unsure of a correct match
DDR PC2100 266Mhz	256MB DIMM	512MB DIMM	1GB DIMM
DDR PC2100 266Mhz ECC	256MB DIMM	512MB DIMM	1GB DIMM
DDR PC2100 266Mhz ECC Registered	256MB DIMM	512MB DIMM	1GB DIMM	2GB DIMM
PC2700 333Mhz 184PIN DDR Memory Upgrades
DDR PC2700 333Mhz	256MB DIMM	512MB DIMM	1GB DIMM
DDR PC2700 333Mhz ECC	256MB DIMM	512MB DIMM	1GB DIMM
DDR PC2700 333Mhz ECC Registered	256MB DIMM	512MB DIMM	1GB DIMM	2GB DIMM
PC3200 400Mhz 184PIN DDR Memory Upgrades
DDR PC3200 400Mhz	256MB DIMM	512MB DIMM	1GB DIMM
DDR PC3200 400Mhz ECC	256MB DIMM	512MB DIMM	1GB DIMM
DDR PC3200 400Mhz ECC Registered	256MB DIMM	512MB DIMM	2GB Kit	2GB DIMM

200 Pin DDR Memory Upgrades
PC2100 266Mhz 200PIN DDR Upgrades
DDR PC2100 266Mhz	256MB SODIMM	512MB SODIMM	1GB SODIMM
PC2700 333Mhz 200PIN DDR Upgrades
DDR PC2700 333Mhz	256MB SODIMM	512MB SODIMM	1GB SODIMM
PC3200 400Mhz 200PIN DDR Upgrades
DDR PC3200 400Mhz	256MB SODIMM	512MB SODIMM	1GB SODIMM

Scan your system to find exact RAM	Have a question on DDR Memory ? Contact Live Help

DDR2 Memory RAM
PC2 3200 400Mhz DDR2 Memory DIMM | PC2 4200 533Mhz DDR2 Memory DIMM | PC2 5300 667Mhz DDR2 Memory DIMM
PC2 6400 800Mhz DDR2 Memory DIMM | PC2 3200 400Mhz  Memory DDR2 SODIMM | PC2 4200 533Mhz Memory DDR2 SODIMM
PC2 5300 667Mhz Memory DDR2 SODIMM | PC2 6400 800Mhz Memory DDR2 SODIMM


DDR2 introduces some new features which allow it to ramp up to much higher speeds (with correspondingly higher bandwidth) and higher memory densities, all the while using less power. DDR2 memory uses a new form factor, a 240 pin DIMM (Dual Inline Memory Module) which is *not* compatible with current DDR memory slots. Upcoming chipsets by Intel and other manufacturers will support DDR2 specifically, and are not backwards compatible.
PC2 3200 400Mhz 240 Pin DDR2 Memory DIMM
DDR2 PC2-3200 400Mhz	512MB DIMM	1GB DIMM	2GB DIMM
DDR2 PC2-3200 ECC 400Mhz	512MB DIMM	1GB DIMM	2GB  DIMM
DDR2 PC2-3200 ECC Registered 400Mhz	512MB DIMM	1GB DIMM	2GB  DIMM	4GB  DIMM
PC2 4200 533Mhz 240 Pin DDR2 Memory DIMM
DDR2 PC2-4200 533Mhz	512MB  DIMM	1GB DIMM	2GB DIMM
DDR2 PC2-4200 ECC 533Mhz	512MB DIMM	1GB  DIMM	2GB DIMM
DDR2 PC2-4200 ECC Registered 533Mhz	512MB DIMM	1GB DIMM	2GB DIMM	4GB DIMM
DDR2 PC2-4200 ECC Fully Buffered 533Mhz	512M DIMM	1GB DIMM	2GB Kit	4GB Kit	8GB Kit
PC2 5300 667Mhz 240 Pin DDR2 Memory DIMM
DDR2 PC2-5300 667Mhz	512MB DIMM	1GB DIMM	2GB DIMM
DDR2 PC2-5300 ECC 667Mhz	512MB DIMM	1GB DIMM	2GB DIMM
DDR2 PC2-5300 ECC Registered 667Mhz	512MB DIMM	1GB DIMM	2GB DIMM	4GB DIMM
DDR2 PC2-5300 ECC Fully Buffered 667Mhz	512MB DIMM	1GB DIMM	2GB Kit	4GB Kit	8GB Kit
PC2 6400 800Mhz 240 Pin DDR2 Memory DIMM
DDR2 PC2-6400 800Mhz	512MB DIMM	1GB DIMM	2GB DIMM	4GB DIMM
DDR2 PC2-6400 ECC 800Mhz		1GB DIMM	2GB DIMM	4GB DIMM
DDR2 PC2-6400 ECC Registered 800Mhz		1GB DIMM	2GB DIMM	4GB DIMM
DDR2 PC2-6400 ECC Registered Low-Profile 800Mhz		1GB DIMM	2GB DIMM	4GB DIMM
DDR2 PC2-6400 ECC Fully Buffered 800Mhz		1GB DIMM	2GB DIMM	4GB DIMM

200 Pin DDR2 Memory SODIMM
PC2 3200 400Mhz 200 Pin Memory DDR2 SODIMM
DDR2 PC2-3200 400Mhz	512MB SODIMM	1GB SODIMM
PC2 4200 533Mhz 200 Pin Memory DDR2 SODIMM
DDR2 PC2-4200 533Mhz	512M SODIMM	1GB SODIMM	2GB SODIMM
PC2 5300 667Mhz 200 Pin Memory DDR2 SODIMM
DDR2 PC2-5300 667Mhz	512MB SODIMM	1GB SODIMM	2GB SODIMM
PC2 6400 800Mhz 200 Pin Memory DDR2 SODIMM
DDR2 PC2-6400 800Mhz		1GB SODIMM	2GB SODIMM

| What is DDR Memory? | Why Use DDR Technology? | DDR Memory at A Glance | Memory Upgrade Websites |
| DDR SDRAM and Rambus RAM | What is RAM and what does it do? | Which DDR RAM? | How to install RAM? | How to identify the size of RAM modules? |
| Different types of RAM? | Mixing brands can often cause problems | Memory Frequently Asked Questions | DDR Memory RAM Upgrade Websites |