1.35V DDR3 memory: how much power does it save?

Posted on 11th Nov 2009 at 10:29 by Richard Swinburne with 5 comments

Richard Swinburne
As soon as Kingston admitted to providing Intel with its 1.35V DDR3 at the IDF Clarksdale demo, we started hearing the buzz from more companies such as G.Skill Press Release, all announcing low voltage DDR3 arriving very shortly.

But what does the drop down to 1.35V bring you? After talking to German journalist, Nico, recently while on a press trip, he informed me that the difference between 1.5V and 1.65V memory works out to be about 10W from the CPU's power draw (as it contains the memory controller), according to his measurements with Lynnfield systems.

That's nearly 10 per cent of a 95W TDP chip, so pretty significant. If we assume the move to 1.35V is another 10 per cent drop, replacing your 1.65V 1,600MHz memory with 1.35V DIMMs could then logically save 20 per cent power for the CPU.

So either we save a few more pennies or, potentially, we have 20 per cent more overclocking headroom. Lovely!

Apparently the current Intel P55 retail board has a beta BIOS supporting 1.35V out the box, but I'd expect QVL certification and new BIOSes across the board in the coming weeks-month from everyone.

We'll be doing our own feature in time to test the power consumption at the wall socket once we get our own 1.35V parts, but it seems like there's lots to look forward to.


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yakyb 11th November 2009, 11:12 Quote
interesting i didnt think it would be that much

my home server was built in an attempt to balance power usage with power! i haven't tried dropping the memory voltage down yet but hopefully i can get the idle to drop a few watts (5 would be nice to get me under 100w)
Jack_Pepsi 11th November 2009, 13:38 Quote
Hmmm... I wonder what happened to Geil's 1.35 modules? Eitherway, I'm definitely interested in lower power modules!

sear 11th November 2009, 14:20 Quote
But, can the lower voltage memory handle fast speeds and timings? What about overclocking? If it's just as capable as current modules then there's no problem, but usually performance for power draw is the trade-off anyone has to make.
wuyanxu 12th November 2009, 00:43 Quote
Asus P7P55D Deluxe 0701 BIOS im running now has vDIMM lower limit at 1.1v........

they can be overvolted to 1.65v right? for monster overclocking
D-Cyph3r 12th November 2009, 15:19 Quote
What are the chances some of these kits are failed/downclocked 1.65v 1800mhz+ kits?
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