First a eulogy for high speed memory –May you find happiness where ever you are. You had been a savior for the few of us who were brave enough to push the envelope of over-clocking. You provided us with a playground to fulfill our hearts craving to run our Core i7s with a 1:1 ratio. RIP!

The nature of the beast has changed forever (at least for the foreseeable future). With Intel locking the clock generator on the platform controller hub (x67 chipset) it is no longer viable to over clock a Sandybridge processor by manipulating the base clock.

The process of over clocking these new CPUs from Intel has become, dare I say it, a very ‘mundane’ task. It is now all based on multiplier manipulation rather than base clock adjustment. Intel charges a small premium for selling multiplier unlocked (ala the extreme editions of yesteryear) and adds a suffix “K” to their model number. Thus the Intel Core i5-2500K is multiplier unlocked while the Core i5-2500 is not.

Thus to over clock a 2500K, simply raise the multiplier and that is it! The memory clock is now unlinked from the processor core frequency as far as over clocking is concerned. Your processor might be running at 5.0GHz and you memory would be happy doing rounds at 1066MHz. No need to fiddle with memory dividers! That is not to say that over clocking memory is not possible; manufacturers can program their motherboard logic to support higher memory speeds. Asus does it, as does Gigabyte.

Foreseeing dark times ahead, OCZ quit memory business to focus on SSDs. It is becoming difficult for memory manufacturers to attract customers to ultra high speed memory with low latencies and low voltage requirements when their practicality is diminishing.

Does all of this doom and gloom mean that there is no place for high speed, low latency memory in the world dominated by the likes of Sandybridge? No far from it! The rules of the game might have changed, but there is still a game to play!

There are manufacturers that are still making products to best utilize the power of these new processors and G.Skill is one of it. The model being tested today, on our newly built Sandybridge rig, is the G.Skill Ripjaws-X 4GBXM 1600Mhz.

The RipJaws-X

Established in 1989 by enthusiasts, G.Skill is a leading memory & Solid State Drive manufacturer based in Taipei, Taiwan. The new Ripjaws-X modules are hand tested on the new Sandy Bridge platform to deliver the best performance and compatibility to the end user.

Memory Facts










1600 mhz



Cas latency

7; works at 6 with default settings

Heat sink

Yes with (shark) jaw like fins!

Tested config.

2x2 gb




The modules come in a clear plastic shell which doubles as a product display package as well. The two Ripjaws-X modules lie side by side over a black information card. The back of the card says that these modules are designed, especially, to work with the new Sandybridge processors.

Memory modules

The memory modules themselves come in a blue heatsink, but like the blue of the Hyper-X modules, only bluer! The front of the modules has a large sticker with the G.Skill and the Ripjaws-X logo. The back of the module has a similar sticker with the all important specifications label.

The heat sink is made of Aluminum. The top of the heatsink has jaw like fins. These are more of a decorative nature, but do serve as heat dissipaters as well. They are only a centimeter tall and thus will not interfere with exotic CPU coolers.

The heatsink resembles the construction of those found on G.Skill Ripjaws (the non-‘X’ variety). There are subtle differences, but the basic design is the same.

The color of heatsink also defines the timings and capacity of the modules. Thus Red modules have CAS latencies of 9 and come in either 2GB or 4GB capacities. The black modules have a CL of 6 and come in 2GB capacity. The blue modules either have a CL of 6 or 7 and come in 2GB capacity.

The ubiquitous cpu-z shot


As these modules are specifically designed for use with Sandybridge processors, the usual over-clocking tests are redundant. Instead the focus will be to run these modules with as tight timings as possible at the listed speed. The memory would be put through its paces by running it as fast as possible with the avail programmed dividers with as loose timings (and as high a voltage) as possible!

Test System


Intel core i5-2500k (stock) + asus p8p67


Kingston hyper-x (2x2gb; ddr3-1600) cl9

Kingston hyper-x blu (2x2gb; ddr3-1600) cl9

Kingston hyper-x lovo (2x2gb); ddr3-1600) cl9

G.skill ripjaws-x (2x2gb; ddr3-1600) cl7


Ati 6950 -2gb


Seagate barracuda 1tb

Test suite

Sandra 2011



Kingston hyper-x low voltage ddr3-1600 cl9


Kingston hyper-x blu ddr3-1600 cl 9


Kingston hyper-x ddr3-1600 cl 9


G.skill ripjaws-x ddr3-1600 cl 8

1. Sandra –memory bandwidth aggregates

The lower latency of the Ripjaws helps it take the first place. I have sneaking suspicion that the ‘made for Sandybridge’ moniker might actually mean something.

2. Mafia II
Mafia II is the long awaited sequel to one of the greatest third person shooter –Mafia. It was selected because of all the games tested this was the one that showed the most “difference” in performance as memory timing were changed. The built-in benchmark tool as used. Just to make sure that the lack of user generated content does not make a difference, the first level was played while benchmarking with FRAPS. (The difference between the two was not statistically significant).

The game was run at 1900 x1200, with all in game settings turned to their maximum. As the testing was done on an ATi video card equipped system, dedicated Phys-X and APEX effects were disabled.

There is minimal of a difference here (~1 FPS; within limits of testing). Games are usually bound by the GPU and/ or the CPU before they are memory bound.

Over clocking

The memory modules were able to run at CAS 6 at 1.50V. This showed marginal improvement in synthetic scores. The memory was able to run at 1866MHz at 1.60V (CAS 9) again yielding gains in synthetic benchmarks.

Notice the bar at the top of the graph. The memory performance improves if the processor is over clocked at the same time as the memory is. Our 2500K was running at 4.5GHz during this benchmarking session. This shows that the memory controller on the processor is able to extract more out of the memory if it runs at higher speeds.

Due to the peculiarities of the Sandybridge platform, the over-clocking options are limited by motherboard design. Our motherboard could support memories frequencies of up to 2133MHz


G.Skill is not so easily cowed out of a market they still see a potential in. They are one of the first with Sandybridge labeled memory modules. Even if they do not offer any technological benefits over ‘off-label’ modules, the buyer is at least assured of guaranteed compatibility with a new platform. G.Skill provides a list of motherboards that work out of the box with these modules.

The modules themselves work flawlessly, even at better timings than advertised.

If you buy these today you will have modules that will run with your high end LGA 1155 motherboards and have enough roars to power the forthcoming refresh of Sandybridge (which presumably natively supports DDR3-1600 speeds). Recommended!


  • Works at CL 6 out of the box
  • Overclocks well (up to 1866MHz)
  • Improved performance with higher processor clock speeds
  • Stylish! (A reason to get an acrylic side window case)


  • Relevance in a changing world

UPDATE: Ripjaw X on Asus Sabertooth P67

We had the opportunity to test these units with Asus’s Sabertooth P67 motherboard flashed to the latest UEFI (V 1053). We ran into some issues trying to get our Sabertooth system stable with the previous UEFI. However with the new version the motherboard was able to push the memory to an impressive 2133MHz. (The rest of the system specs remain as described above).

The results in asterisk show the memory bandwidth with the processor over clocked to 4.5GHz!

With the thorny issue of memory compatibility ironed out, I can safely say that this is one of the best high speed memory modules available for the Sandy Bridge platform today!

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