1.35V DDR3 memory: how much power does it save?
Posted on 11th Nov 2009 at 10:29 by Richard Swinburne with 5 comments
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.