The G.Skill ECO DDR3 Series


So-called "Green" products are all the rage lately and G.Skill has decided to cash in on this trend with their ECO series of DDR3 memory modules. Designed for Intel's Core i5 and Core i7 Lynnfield processors, the ECO series operates at a low 1.35vdimm versus your typical 1.65vdimm modules. This particular kit, the F3-12800CL7D-4GBECO, sports 7-8-7-24 timings at 1600MHz while scraping by with a meager 1.35vdimm. It feels like only a year ago we were blasting 2.3vdimm through DDR3, now we are down to 1.35vdimm!

G.Skill DDR3-1600C7 ECO 1.35vdimm

Through the systematic shrinking of manufacturing technologies and binning of memory chips, G.Skill is able to offer a large line of ECO memory kits that sport the power sipping 1.35vdimm that make this kit so interesting. Back in October 2009 G.Skill posted a news post indicating there would be six 4GB memory kits available covering DDR3-1333 and DDR3-1600 with CAS7, 8, and 9 supported. Checking today on Newegg there are now 10 kits available including four 8GB kits that give the consumer a slight price drop for buying memory in bulk. Compared to other 8GB memory kits the ECO actually have competitive timings even with their 1.35vdimm making the ECO even more attractive.

Key Features

G.Skill DDR3-1600C7 ECO 1.35vdimm

Since this is a low voltage kit and I'm an overclocker at heart the first thing that came to my mind was overvoltage scaling! First up though is a quick peek at the kit, the heatspreaders, and the lovely Georgia pollen that is currently covering my desk. Then we'll tear into the kit and see what it can really do when it is pulled off that harsh voltage diet.

G.Skill DDR3-1600C7 ECO 2x2GB Kit

G.Skill DDR3-1600C7 ECO 1.35vdimm

I found the kit to have a rather nice set of gray heatspreaders that made life miserable in getting the right white balance. Above you can see one of the best photos that accurately displays the sticks color. The backside of the packaging had an interesting tidbit regarding the sticks themselves.

G.Skill DDR3-1600C7 ECO 1.35vdimm Packaging

To further reinforce the efficient nature of these sticks G.Skill applied a little blurb to the back of the packaging. With all the mention of environmental friendliness and lower voltages it made power consumption testing a big priority.

G.Skill DDR3-1600C7 ECO 1.35vdimm

This image is a bit washed out but you can see the G.Skill design and the abstract blade design etched into the heatspreaders. It was interesting seeing how little heat these sticks emitted compared to my higher voltage memory kits. We might be getting to the point where the heatspreaders were insulating the sticks rather than helping to dissipate the heat. 

G.Skill DDR3-1600C7 ECO 1.35vdimm

Not sure what exactly the G.Skill logo is meant to represent. Let's pretend it is a space-ship going pew-pew across the galaxy.

G.Skill DDR3-1600C7 ECO 1.35vdimm

The product code is easily decipherable. F3 -> DDR3, 12800 -> DDR rating, CL7 -> CAS7. No clue on the D, but 4GB and ECO are self explanatory. Since I'm 0-2 in removing heatspreaders I'm going to leave these beauties alone but I don't think we're in for any shocking surprises.

Test Configuration

G.Skill DDR3-1600C7 ECO 1.35vdimm

G.Skill DDR3-1600C7 ECO 1.35vdimm test system

Today's testing was performed with my beat up Core i7 860ES and the Asus P55 Maximus III Extreme. Windows 7 Professional x64 with the Catalyst 10.3 drivers were used with the HD5870 at reference clocks. Memory primary timings were manually set according to the results graph and secondary timings were left on auto with b2b disabled. vCore was set to 1.25v, vtt set to 1.35v, and vdimm set to 1.35v, 1.55v, 1.65v, and 1.75v for the tests. Overclocking stability was considered to be achieved when Super Pi 32M completed 1 run without errors. Reference benchmarks were performed at speeds considered stable for CAS7, CAS8, and CAS9.

Intel P55 Test Platform



Live Pricing


Intel Core i7 860


Asus P55 Maximus III Extreme


G.Skill DDR3-1600C7 2x2GB ECO

Video Card

Asus HD5870 1GB

Hard Drive

Seagate 7200.10 320GB


Dimastech Bench Table Hard V2


Cooler Master Hyper 212 Plus

Power Supply

Corsair HX1000

Operating System

Windows 7 Professional x64

Test Results

For the performance numbers I chose four separate timing/frequency settings that were stable with this kit. By using a combination of CPU multipliers and memory dividers I was able to keep the CPU within 20MHz of 3040MHz in an attempt to eliminate the CPU from the performance differences.

G.Skill ECO Series 1600C7 WinRAR

G.skill ECO Series 1600C7 Cinebench R10

G.Skill ECO Series 1600C7 SuperPi 32M

G.Skill ECO Series 1600C7 Sandra 2010 Memory Bandwidth

G.Skill ECO Series 1600C7 Sandra 2010 Multimedia

G.Skill ECO Series 1600C7 Sandra ALU/FPU Aggregate Performance

G.Skill ECO Series 1600C7 3DMark vantage

G.Skill ECO Series 1600C7 Heaven DX11 1280x1024

There is a lot of data here but a few trends formed through the results. For the most part the stock speed and timings were optimal with only few bandwidth scaling applications like WinRAR SMP and Sandra 2010 Memory Bandwidth gaining from the looser DDR3-1900 9-11-9-27. Keep in mind that these high speeds required additional operating voltage which goes against the original purpose of the kit. In the end it appears to be best to leave the kit with the stock 1.35vdimm and hover around DDR3-1600 7-8-7-24.

Power Consumption & Overclocking Results

G.Skill DDR3-1600C7 ECO 1.35vdimm power consumption testing

I decided to kick this off with the power consumption results. After all, this kit's main selling point is the low operating voltage. These numbers were measured with a Kill-a-watt with a Core i7 860 operating at 160x19 for 3040MHz with 1.25vcpu, 1.30vtt, and the memory running at 1600MHz. EIST was enabled for additional power savings at idle. The 1.65v results were achieved with Corsair Dominator GT modules running the same settings but with 1.65vdimm. From what we can see the difference isn't much but it was solid enough to document. The worst delta, 9 watts in 3DMark Vantage, is only a 3% power savings. However I imagine in a system where the memory forms a larger portion of the power budget, say a dual socket server with 128GB of memory, would see much larger savings. Progress is progress I suppose.

G.Skill DDR3-1600C7 ECO 1.35vdimm timing and voltage scaling

 Since these are low voltage sticks I figured I should see some healthy frequency scaling with increases in voltages. This couldn't be further from the truth. I originally planned on testing up to 1.65vdimm but when I didn't see much in the way of scaling I went to 1.70 vdimm, 1.75vdimm, and even 1.80vdimm, a 33% boost in voltage. Turns out these sticks hardly scale with volts past 1.55vdimm. Rather, they scale by loosening the timings with a decent overclock to DDR-1900 achieved with 9-11-9-27 timings and 1.55vdimm. I suspect with further investigation whatever is holding the sticks back could be uncovered.


Right before I wrapped this article up I decided to give the sticks one last go to try and break DDR3-2000. Turns out the sticks aren't voltage limited but tRCD limited. Loosening the timings to 9-12-10-30 let the sticks pass at DDR3-2030, a modest 6% bump over the DDR3-1900 9-11-9-27. This was also with only 1.55vdimm, turns out more vdimm didn't help stability.

G.Skill DDR3-1600C7 ECO 1.35vdimm at DDR3-2030

Dropping to 10-13-10-30 let the sticks scale a bit more but Super Pi 32M was only stable past DDR3-2070 and the performance was terrible. That covers it for the overclocking with these sticks. Better off leaving them at stock and using them for their low voltage requirements.


G.Skill DDR3-1600C7 ECO 1.35vdimm

G.Skill's ECO series is quite the kit when you consider what it is able to accomplish with what it is given. DDR3-1600 with only 1.35vdimm may become commonplace in the future but for now it is a nice surprise. Priced at $124.99 plus $2.99 for shipping, the G.Skill ECO DDR-1600 2x2GB are priced $15 above the lowest priced 4GB DDR3 1600MHz dual-channel memory kit, but it is priced among the majority of other DDR3-1600 C7 kits. It might be worth considering the powersavings from these sticks versus your typical 1.65v or higher kits but we are also talking about fractions of a penny a day.

G.Skill DDR3-1600C7 ECO 1.35vdimm

Like most if not all memory manufacturers, G.Skill offers a lifetime warranty on their memory kits. However with the low voltage I doubt this will ever need to be called into service. As I mentioned earlier these sticks run very cool to the touch so accelerated degradation due to heat should not be an issue. Scanning the internet for customer reviews reveals a high level of satisfaction with the kit. However a good point to note is that these sticks were binned for Lynnfield processors. There is no guarantee that they will do DDR3-1600C7 with 1.35v on LGA1366 or AMD AM3 motherboards. Perhaps we will see G.Skill X58 ECO kits in the near future if demand is high enough.

G.Skill DDR3-1600C7 ECO 1.35vdimm

Like most memory reviews it is tough to measure between what could be the margin of error to determine performance. Memory subsystems have become so efficient regardless of the memory used that you have to look for other differing factors when measuring a kit's value. I feel like a broken record saying this but the kit does work as advertised and runs on a lower operating voltage which resulted in cooler running sticks and lower power consumption. Overclocking performance was what I'd consider to be marginal but logically it makes sense for a low-power kit to not scale to high frequencies. In the end it comes down to the fact that at stock the sticks are rather nice for $124.99 and they deliver on all the promises made on the packaging. To wrap everything up they also look rather nice; I guarantee my photos do not do them justice.

Legit Bottom Line: G.Skill's ECO series delivers excellent performance while keeping power consumption in check.