DDR, DIMMS and SODIMM are both memory modules used in computers. DIMMs are used in desktop computers and servers. A DIMM (133MM) is about twice as long as a SODIMM (67MM). DIMMs can carry features not normally found on SODIMMs such as ECC and REGISTERED. SODIMMs are used in notebook computers.

The SPD (Serial Presence Detect) chip on a memory module is an additional chip holding 128Hex bytes of information about the module. This identifies the module to the BIOS during POST so the Motherboard knows its characteristics and timings that can be used. This was introduced at the same time as SDRAM.

The most common reason is that the machine is designed to work in Dual Channel Mode where the memory controller utilises a pair of modules in turn (interleaving) so that it can reduce the time that it waits whilst the memory is read giving a better performance.

JEDEC is the Joint-Electron-Device-Engineering-Council, an important body that sets the standards in the memory industry. Areas like the dimensions and functionality of DIMMS are set by JEDEC. This ensures compatibility.

Memory cards and USB drives are NOT designed for long term storage. You should always backup your data on to another device. The data will normally stay valid for a period of up to 10 years if stored under normal conditions. The data cells inside carry a charge which can dissipate over time. The data can be refreshed; copy all data off card and then format the card or USB drive and then restore all data to extend the data for another 10 years.

Your data on the USB Flash Drive can become corrupted or lost and the file system of the Flash Drive may become corrupted as well. It is always recommended to use the "Safely Remove Hardware/USB" option when using your Flash Drive on a PC or Mac.

Yes, you can use a USB 3.0 Flash Drive on USB 2.0 devices now, as they are backwards compatible. When you upgrade to a USB 3.0 system in the future, such as a new PC with Windows 8 (and certain new Apple Macs) you can then benefit from the faster "SuperSpeed" data transfer rates. We have also found that our USB 3.0 Flash Drives perform faster on USB 2.0 systems then current USB 2.0 Flash Drives.