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How Much Power Does Low-Voltage DDR3 Memory Really Save?

How Much Power Does Low-Voltage DDR3 Memory Really Save?
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Kingston’s HyperX LoVo-series DDR3 memory allows users to reduce voltage to 1.35 V or 1.25 V in order to save power and allegedly decrease system temperature. We test the eco-friendly modules to find out if it really makes sense to run undervolted memory.

Practically every segment of the hardware market now has so-called "green" products. These aim at all of our environmental consciences by being "eco-friendly," often trying to save money by reducing power consumption. This describes Kingston’s new HyperX LoVo series, which runs typical DDR3 memory speeds at decreased voltage settings. To examine Kingston's eco claims, we tested the KHX1600C9D3LK2/4GX, more easily referred to as the DDR3-1600 2 x 2 GB kit.

The Power Consumption Story

Low-power hardware is certainly more popular in Europe than in North America, as average energy costs are lower in the U.S., causing the average European to be more fastidious about power consumption.

With that said, there are two aspects to low power products: the environment and the cost of your energy bill. The environment may benefit from decreased hardware power consumption. We emphasize only the possibility of a benefit because the power and natural resources (including fresh water) required to produce and recycle or dispose of a piece of hardware is typically ignored in the energy equation. All should be part of a larger resources balance sheet, but commercial marketing only goes half-way. This is why we prefer not to stress the "green" factor too much and limit our statements to power reduction.

Low Voltage = Low Power

Let’s look at power consumption. In this particular case, we decided to examine system memory, a component that's typically overlooked because it doesn't require a lot of power to operate compared to a processor or graphics card. Users and memory vendors typically focus on higher memory speeds, and few would justify reducing memory speeds in order to decrease power consumption. However, more advanced silicon often allows reductions in operating voltage. We’ve seen this in processors many times, and Kingston has begun to apply this to memory.

The HyperX DDR3 LoVo-series caters to upper-mainstream DDR3 speeds, meaning DDR3-1333 and DDR3-1600, and the product offers the performance you expect at decreased voltage. But given that memory only requires a few watts of power anyway, we had our doubts about the overall gains available. Does this really have a noticeable impact on total system power? And will these modules perform similarly to those running at more standard voltages?

DDR3 Memory Overview

Most desktop-class systems available today from AMD or Intel use DDR3 memory. This is the case for all systems based on AMD’s Socket AM3 and Intel’s LGA 1366 and LGA 1156 interfaces. The LGA 775-based platform can use either DDR2 or DDR3 memory.

Desktop DDR3 comes on 240-pin DIMMs while notebook DDR3 arrives on 204-pin SO-DIMMs. DDR2 desktop RAM has the same amount of pins (200 pins for DDR2 SO-DIMMs), but different notches to avoid mixing them up, since they’re electrically incompatible.

DDR3 was specified by the JEDEC Solid State Technology Association to run between 1.5 V and 1.575 V (a 30% drop from DDR2's 1.8 V), and to withstand voltages of up to 1.975 V before taking damage. The prefetch buffer was doubled from DDR2's four bits to eight bits, which is why the effective bandwidth doubled from between DDR2-400 and DDR2-800 to DDR3-800 to DDR3-1600. Double data rate (DDR) means that data is transferred during the falling and the rising edge of the clock signal. In a simple example, DDR3-1600 is based on double data rate, hence the physical memory I/O clock is 800 MHz.

Many memory products on the market were designed for clock speeds beyond JEDEC's specs. We've already seen DDR3-2400. However, such speeds require a significant voltage increase to maintain memory reliability. On the other hand, lower memory speeds may still be reliable at decreased voltage. Enthusiasts typically make their way through the BIOS-level parameter jungle, but regular users can still access two mechanisms for basic settings and system tuning.

Viable memory settings are typically taken from a memory module’s Serial Presence Detect (SPD) ROM, where all memory products store their timing parameters. Each clock speed setting requires different parameters to operate, and motherboards usually utilize the SPD defaults unless you want to tweak your system and overclock your memory along with other components. Intel added extensions to the SPD that are called Extended Memory Profile (XMP). This addition seamlessly utilizes unallocated bytes on the EPROM. If memory is XMP-compliant, then it's possible to have your motherboard and tweaking software use the most appropriate XMP profiles to achieve your overclocking goals. But again, this can also optimize memory in the opposite direction to reduce power and decrease operating temperature.

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Top Comments
  • 22 Hide
    Anonymous , July 17, 2010 9:34 AM
    Hey, that 4W under load is 2W per module.
    If you use a server with 18 ram slots filled, then that is 32W in all.
    In the 32 ram slot Tyan s8812 it would mean 64W in power consumption.

    Taking that these systems run like 0-24 7 days a week, it DOES count....
  • 19 Hide
    eugenester , July 17, 2010 6:26 AM
    Hah, I knew that this whole "green memory" thing was just an eco-fad. Memory sticks usually consume as much as generic case fans and usually lower. Why pay a premium for the same performance but a ~1 watt - 4 watt difference?
  • 15 Hide
    madvsfool , July 17, 2010 6:34 AM
    Low voltage memories like Kingston LoVo or G.Skill Eco doesn't necessarily mean reducing energy consumption. Low voltage can reduce heat produced, and also provide high oc potential under 1.65v. I got my G.Skill Eco 1.35v DDR3-1600 7-8-7 overclocked to 1.65v DDR3-2220 10-11-10.
Other Comments
  • 19 Hide
    eugenester , July 17, 2010 6:26 AM
    Hah, I knew that this whole "green memory" thing was just an eco-fad. Memory sticks usually consume as much as generic case fans and usually lower. Why pay a premium for the same performance but a ~1 watt - 4 watt difference?
  • 15 Hide
    madvsfool , July 17, 2010 6:34 AM
    Low voltage memories like Kingston LoVo or G.Skill Eco doesn't necessarily mean reducing energy consumption. Low voltage can reduce heat produced, and also provide high oc potential under 1.65v. I got my G.Skill Eco 1.35v DDR3-1600 7-8-7 overclocked to 1.65v DDR3-2220 10-11-10.
  • 8 Hide
    masterjaw , July 17, 2010 8:23 AM
    ^ That must've been the real use for those low voltage RAMs. A greater headroom for overclocking. But in stock, the only thing IMO that you could benefit from it was lower heat produced (which is negligible if you have a mem cooler and a good case airflow).
  • -5 Hide
    misha87 , July 17, 2010 8:38 AM
    th
    madvsfoolLow voltage memories like Kingston LoVo or G.Skill Eco doesn't necessarily mean reducing energy consumption. Low voltage can reduce heat produced, and also provide high oc potential under 1.65v. I got my G.Skill Eco 1.35v DDR3-1600 7-8-7 overclocked to 1.65v DDR3-2220 10-11-10.


    well u are right u can overclock it more at a lower voltage and u are kinda of wrong when u said it doesn't necessarily reduce energy, u should do some research of the loVos and compare them the regular ram and you will find that the ram do has lower energy consumption
  • 5 Hide
    rohitbaran , July 17, 2010 9:21 AM
    Well, the increment in price isn't worth the saving if we compare it to increment in a power saving motherboard, or GPU. This should be something like coup de grace in designing the ultimate low power system, but definitely not the first step.
  • 22 Hide
    Anonymous , July 17, 2010 9:34 AM
    Hey, that 4W under load is 2W per module.
    If you use a server with 18 ram slots filled, then that is 32W in all.
    In the 32 ram slot Tyan s8812 it would mean 64W in power consumption.

    Taking that these systems run like 0-24 7 days a week, it DOES count....
  • -5 Hide
    lashabane , July 17, 2010 9:59 AM
    CadilLACiHey, that 4W under load is 2W per module. If you use a server with 18 ram slots filled, then that is 32W in all.In the 32 ram slot Tyan s8812 it would mean 64W in power consumption. Taking that these systems run like 0-24 7 days a week, it DOES count....

    In this specific instance, then yes it does count. However, consider that most readers on this site are users and not server operators. Also consider the added cost of populating all those RAM slots with more expensive RAM. These modules cost ~$170 for 4GB of DDR3-1333. You can pick up some G.Skill off Newegg for $81. Multiply the difference by 8 to populate all slots in the Tyan s8812 and you're talking about an extra $712.
  • 1 Hide
    Zenthar , July 17, 2010 11:34 AM
    It never even crossed my mind to use low-voltage RAM as a mean to save power. To me the whole point of low voltage is either better overclocking headroom or lower heat output (and even that I'm not sure).
  • 8 Hide
    ares1214 , July 17, 2010 12:11 PM
    this doesnt make sense to me, considering a lot of the eco sticks are the exact same price as corresponding non-eco sticks, yet usually oc better:

    http://www.newegg.com/Product/Product.aspx?Item=N82E16820231321

    100 bucks for that, i think ill take it.
  • -4 Hide
    fausto , July 17, 2010 2:13 PM
    ares1214this doesnt make sense to me, considering a lot of the eco sticks are the exact same price as corresponding non-eco sticks, yet usually oc better:http://www.newegg.com/Product/Prod [...] 6820231321100 bucks for that, i think ill take it.




    read some of the reviews on that post and to be honest...who the fuck buys eco friendly memory and expects it to be an overclocking champ and complaints about the heat sinks quality. seriously?
  • 0 Hide
    triplebug , July 17, 2010 3:33 PM
    So for RAM it saves nothing :/ 
  • 3 Hide
    mitch074 , July 17, 2010 4:03 PM
    Personally, apart from fine-tuning my processor's CPU clock driver, the most power-sensitive steps I took were:
    - using a large Heat sink with a slow fan
    - using two 2.5" HDD in RAID 1 (the actual concern was on data safety, but power was a concern too)
    - modifying my Radeon 4850's BIOS to use much, much lower voltage and clock speed when idle: 0.93 V and 160/500 MHz instead of 1.1V and 500/900 MHz. Probably cut the power requirements by 30W.
  • 0 Hide
    Agges , July 17, 2010 4:33 PM
    So there is a (small) point to LoVo ram instead of the silly Watt-usage comparisons done when SSDs are benched..
  • 2 Hide
    omoronovo , July 17, 2010 5:47 PM
    Test using a core i7 rig. Bit-tech.net did a similar comparison of these same modules 4 months ago. The reduction in voltage from "standard" 1.65v ddr3-1333 memory to these modules at 1.2v ddr3-1333 reduced system load wattage from 193w to 166.

    THAT is a considerable gain, and I am disgusted that Toms chose to bench a single test configuration here - the IMC's in AMD and Intel chips are markedly different, and the only reason DDR3 is being made at this voltage is because Intel designed it's nehalem chips around the 1.5v DDR3 specifications standard, forcing manufacturers to start binning for voltage and not just speed as they had been doing previously.

    For anyone interested, here's the feature article from bit-tech: http://www.bit-tech.net/hardware/memory/2010/03/18/kingston-lovo-power-saving-1-25v-ddr3-ram/1
  • 0 Hide
    cyberkuberiah , July 17, 2010 6:51 PM
    any meaningful power saving can only come from the components that consume it in the first place : and that would be your graphics and cpu . from two sources : chip level power management (in tandem with the OS) and the fabrication (NM) of the chip itself .

    i will hopefully replace my 5850 with something 28nm . someone (long back) on tom's said that graphics are going to be saturated , well , no . forget eyefinity , even with single monitors , the newer games will require a lot of juice , considering the holy grail - photo realism is still far .
  • 0 Hide
    WarraWarra , July 17, 2010 7:06 PM
    I can imagine this is much more exaggerated with DDr2 2.1V running at 1.4V and 667mhz instead of stock 1066mhz .

    The gigabyte mboard on demand tool helps a lot with power saving as well.

    I think when the yearly bill gets cut down by $50.00 or more then people will start taking this serious or spend the money on burgers / beer instead.

    Servers centre's with this low power ram or corporate company's 100 or more pc's will see a lower bill using low power parts and under clocking.
  • 0 Hide
    eddieroolz , July 17, 2010 7:57 PM
    Honestly memory modules weren't the first thing that sprung to my mind when it comes to low-power components. But on the other hand, since it runs at frequencies with lower voltage than normal modules, I'm sure this will be a great potential for overclocking.
  • 1 Hide
    exodite , July 17, 2010 8:59 PM
    For consumers it seems to me this kind of low voltage memory should have been provided as SO-DIMMs for notebook use as the first market. Even a few watts could have a reasonable impact on battery life in such a platform.

    For a desktop it seems pretty negligible though.
  • 3 Hide
    hunter315 , July 17, 2010 11:53 PM
    Why were the kingston sticks chosen over the significantly cheaper Gskill Ecos?

    As was mentioned up above, any chance we can get an OCing test done on the regular kit vs the low voltage kit?
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