Memory - DDR2 DDR3 SDRAM
Memory is the name given to silicon chips that stores volatile computer data. Volatile means that the contents of memory will be lost if the power of the computer is switched off. Memory stores some of your operating system and application data while it is being run. The more memory you have in your system, the more application you can run simultaneously and will provide an overall better system performance.
Memory comes in many form. The older systems use SDRAM, while the current systems use DDR2 or DDR3 SDRAM (Double Data Rate Synchronous Dynamic Random Access Memory).
Depending on the motherboard you choose you need to select the matching compatible memory. For example if you buy an Intel motherboard for an Intel Core 2 Duo CPU then it will support Dual-channel DDR2 800, 667 or 533. Therefore you can buy any DDR2 memory at those speeds. However DDR2-800 memory will run the CPU bus at the optimal speed while slower memory are backward compatible. It is recommended that you get the highest memory speed your motherboard supports if you want the maximum performance. If you are on a budget then slower speed memory would be sufficient. Please note, DDR-2 memory must be run in pairs to run at double data rate. So if you decide to get 2GB of memory then you need to buy 2 x 1GB modules. It is also best to get both pairs of memory from the same manufacturer to avoid incompatibility.
Most AMD Athlon 64 X2 and Phenom processors also support DDR-2 at speeds mentioned above.
If you have the latest Intel i7 motherboard then you will need a triple-channel DDR3 1600, 1333, or 1066.
It is always best to ask your retailer or check the manufactures website to make sure that your chosen memory is compatible with your chosen motherboard. Some of the well known memory manufactures are Crucial, Kingston, Corsair, and Samsung. The following list shows all the current types of DDR2 and DDR3 memory.
DDR2 Memory:
| Memory name | I/O Bus Speed | Module name |
| DDR2-400 | 200 MHz | PC2-3200 |
| DDR2-533 | 266 MHz | PC2-4200 |
| DDR2-667 | 333 MHz | PC2-5300 |
| DDR2-800 | 400 MHz | PC2-6400 |
| DDR2-1066 | 533 MHz | PC2-8500 |
DDR3 Memory:
| Memory name | I/O Bus speed | Module name |
| DDR3-800 | 400 MHz | PC3-6400 |
| DDR3-1066 | 533 MHz | PC3-8500 |
| DDR3-1333 | 667 MHz | PC3-10600 |
| DDR3-1600 | 800 MHz | PC3-12800 |
