The technology and how it works
As stated in the DDR / DDR2 HEXUS.help guide, random access memory (RAM) is commonly one of the first places to look when contemplating a system upgrade. Today, that upgrade for many users may revolve around a transition to DDR3, successor, of course, to DDR2 and DDR before it.
DDR3, which stands for double-data-rate three synchronous dynamic random access memory - thank goodness for the acronym - is an evolution of RAM and provides key improvements such as greater performance and reduced power consumption.
Operating at a voltage of 1.5V, DDR3 will consume approximately 30 per cent less power than DDR2, which operates at 1.8V. That advantage alone is significant in portable systems such as notebooks, where the use of DDR3 as opposed to DDR2 will improve battery life.
The most important feature of DDR3, however, is its improvement in performance. Thanks to its 8-bit-deep prefetch buffer (twice that of DDR2), DDR3 offers far-greater bandwidth and can achieve data transfer rates of 800MHz - 1,600MHz. In contrast, DDR2's data transfer rate manages up to 1,066MHz.
Despite the improvement in data rates, DDR3 offers somewhat misleading latencies. The general idea is that lower latencies result in better performance as data can be accessed quicker. DDR3's latencies, however, are generally higher than latencies of DDR2. Don't let that put you off, though. DDR3's latencies are measured in shorter clock cycles, meaning that a higher-rated latency when compared to DDR2 doesn't equate to reduced performance.
It all sounds very good, but there are disadvantages to be aware of. DDR3 memory modules may be the same physical size when compared to DDR2, but they are not backward-compatible. In other words, DDR3 memory modules won't work in a motherboard whose memory slots only support DDR2. A DDR3 upgrade, then, could mean upgrading your motherboard, too.
The second disadvantage, and perhaps DDR3's biggest hurdle to date, is cost. Having first appeared back in 2005, DDR3 has fallen in price over the past three years, but in many cases can still cost up to, or beyond, twice that of a similar-capacity DDR2 alternative.
As a result of its high asking price, DDR3 has taken a while to garner widespread adoption. Indeed, even today, DDR2 remains a hugely popular solution as a result of its far-lower cost.
The slow adoption is also a result of supporting hardware from big names such as Intel and AMD. Intel, the world's largest semi-conductor manufacturer, first announced DDR3 support for its mainstream desktop platforms in 2007. AMD, however, is yet to join the party and will announce its first DDR3-supporting desktop CPUs in early 2009.
It's a slow journey, but it's heading for an inevitable outcome. DDR3 will, one day, become the most common memory solution. In November 2008, Intel will launch its next-generation Core i7 processor - a chip that supports only DDR3. Such developments will ultimately help accelerate the phasing in of DDR3, and it's destined to become the memory of choice in 2009.
Once established as the firm favourite, DDR3 is on course to remain so until at least 2012 when the more efficient and quicker DDR4 is expected to make its debut.
As with DDR2 and DDR before it, DDR3 providers need to be distinguished between the chip makers and module makers.
Module makers - such as Corsair and Crucial to name just a few - will purchase the chips used in their modules from chip makers such as Samsung and Micron.
Should a module from two different manufacturers feature chips from the same source, users shouldn't expect identical performance. The development of RAM modules includes various designs and varying levels of testing. Cheaper modules, for example, may fail to pass tests at higher speeds.
With DDR3 becoming increasingly popular, there's now a well-populated list of DDR3 manufacturers, and plenty of choice for the consumer.
DDR3 has taken a while to firmly establish itself as a true successor to DDR2. Nonetheless, with prices beginning to fall, and DDR3-only hardware such as Intel's Core i7 on the way, it's all but ready to take the place of DDR2.
Don't be at all surprised to find your next notebook or desktop system to be equipped with DDR3.