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DDR3 RAM: System Memory Technology Explained E-mail
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Written by Olin Coles   
Sunday, 11 May 2008
Table of Contents: Page Index
DDR3 RAM: System Memory Technology Explained
DDR3: Efficiency
Prefetch Buffer and Speed
Overclocker Functionality
Final Opinion on DDR3 RAM

DDR3: Efficiency

Efficiency is a double-edged sword when we talk about DDR3, because aside from fabrication process efficiency there are also several architectural design improvements which create a more efficient transfer of data and a reduction in power. All of these items tie in together throughout this article, so for you to understand why DDR3 is going to be worth your money, you should probably also know why it's going to deliver more.

Power Consumption

So lets begin with power: at the JEDEC JESD 79-3B standard of 1.5 V, DDR3 system memory reduces the base power consumption level by nearly 17% compared the 1.8 V specified base power requirement for DDR2 modules. Taking this one step further, consider that at the high end of DDR2 there are 1066 MHz memory modules demanding 2.2 V to properly function. Then compare this to the faster 1600 MHz DDR3 RAM modules operating at 1.5 V nominal and you'll begin to see where money can be saved on energy costs - conserving nearly 32% of the power previously needed. The reduced level of base power demand works particularly well with the 90 nm fabrication technology presently used for most DDR3 chips. In high-efficiency purposed modules, some manufacturers have reduced current leakage even more by using "dual-gate" transistors.


You might be wondering how big a difference 0.7 V can make on your power bill, and that's a fair concern. In reality, it's not going to be enough to justify the initial costs of the new technology, at least not for your average casual computer user who operates a single workstation in their home. But before you dismiss the power saving, consider who might really make an impact here: commercial and industrial industries. If the average user can see only a few dollars saved per month on utility costs, imagine the savings to be made from large data center and server farm facilities. Not only will the reduced cost of operation help minimize overhead expenses, but the improved design also reduces heat output. Many commercial facilities spend a double-digit portion of their monthly expenses on utilities, and the cost savings sustained from lower power consumption and reduced cooling expenses will have an enormous effect on overhead. If you can imagine things just one step further, you'll discover that reduced cooling needs will also translate into reduced maintenance costs on that equipment and prolong the lifespan of HVAC equipment.

Voltage Notes for Overclockers

According to JEDEC standard JESD 79-3B approved on April 2008, the maximum recommended voltage for any DDR3 module is must be regulated at 1.575 V (see reference documents at the end of this article). Keeping in mind that the vast majority of system memory resides in commercial workstations and mission-critical enterprise servers, if system memory stability is important then this specification should be considered the absolute maximum voltage limit. But there's still good news for overclockers, as JEDEC states that these DDR3 system memory modules must also withstand up to 1.975 V before any permanent damage is caused.



# DD3 ExplainedGordon R 2010-03-06 16:50
I commend you for taking on this task and for the excellent job you did in explaining the technology. By reading this article I was able to avoid making some potentially costly and irrevelent purchases. Keep up the good work!
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# good1markIV 2010-09-22 08:39
good to great explanation. keep it on.
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# Nice OneDerek 2011-07-26 23:36
Its great to see someone that has the passion to do a test like this, in order for the novoice PC user to increase memory for better performance! Having said this and recently a iMac convertee, Am I wasting my time increasing the DDR3 memory for bette performance?
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# RE: Nice OneDavid Ramsey 2011-07-27 06:57
Yes, you'd be wasting your time, since you can't tweak the memory timing on any Mac. You can put faster memory in it, but it will run at whatever speed is built into the machine. You can, of course, tweak memory timing to your heart's content on a Hackintosh.
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# Nice One v1Derek 2011-07-27 23:31
Thanks David, I may have misled you. I was refering to increasing the memory from a standard 8MB to 16MB. As you maybe aware that the new iMac has a 2 slot "option" underneath the monitor.
I was not refering to any of the above you mention! As I do not understand "memory timing" Ihope this explains it better.
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# RE: Nice One v1David Ramsey 2011-07-28 08:13
Sorry, I misunderstood. Yes, more memory is always better!
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