What You Need To Know About Server Memory

The first thing we need to talk about is DDR, which is a double data rate, which is the current state of all memory. Since the release of DDR, it has gone through several generations of DDR, DDR2, DDR3, and now DDR4. These different generations of memory vary in speed due to the increased peak transfer rates due to technology.

DDR2 speed

DDR2 was new in 2003 and started with a peak transfer rate of 3200MB / s. Eventually, DDR2 transfer rates became available on 4266, 5333, and even 6400. PC2-5300 was most commonly used after it became widely accepted. It is still used by many servers and can be purchased for older machines.

DDR3 speed

DDR3 appeared in 2007, and the speed has increased accordingly. There are measurements of speeds other than peak transfer rates, such as data rates measured with MT / s and I / O bus clocks, but for the sake of simplicity, this article sticks to peak transfer rates. DDR3 started out at speeds of 6400, but more commonly used are speeds such as 8533, 10666, and 12800. There are also 14933 and 17066 PC-3 or DDR3, but the most widely used speed.

DDR4 speed

In 2012, JEDEC, which oversees the technical specification for uniformity, released the DDR4 standard. Comes with new DDR4 memory with peak transfer rates including 12800, 14933, 17066, 19200MB / s. As with other memory migrations, the speeds that were available in the latest generation are rarely used because high speeds are now widely accepted.

For each new generation, there is a difference in the keyhole, which is a slot to verify that the correct memory module is being used. The wrong generation of memory cannot be used on machines that do not support it. The key slot also prevents the wrong module from being inserted.

Other variations of server memory include unbuffered, full buffer, or registration. Many servers can use only unbuffered, registered, or fully buffered memory. The difference is the memory response to the specified information. Unbuffered memory is generally not ECC because there is generally no error checking and correction. Fully buffered and registered memory includes error checking and correction.

In addition to checking and correcting errors, there is an extra chip in registered and fully buffered memory. This chip communicates directly with the CPU and then distributes the information to be processed to the memory modules of other chips. In unbuffered memory, the CPU needs to send information to the individual chips on the memory module. This means that using unbuffered memory increases the CPU load if it is registered or fully buffered. Fully buffered ones are widely used in DDR2 because DDR3 is no longer registered or buffered away from it.