OCZ Blade 3x2GB PC3-17000 CL8 Memory Review

Stability Testing & Overclocking

For new readers to our memory reviews here at Hardware Canucks, this is our little spiel on memory stability. There are many different views on testing stability and we don't claim ours to be the best, we are simply very open and forward with what we think constitutes stable:

Memory stability, what constitutes stable? What is not considered stable? These questions get hotly debated in enthusiast forums all over the internet like little brush fires on the fringe of an inferno that play havoc with forest fire crews. Everyone has their own opinion about stability, especially when it comes to memory stability. For some, stable means they can do whatever it is on their computer without it crashing, blue-screening, or restarting; whether that means gaming or just surfing the internet. To this user, stable means simply using the computer as they normally would.

Of course, that is not what we would call stable and we do a lot more thorough testing before labeling a memory frequency/timing stable. One of the toughest types of programs on a system has been found to be distributed computing projects such as Rosetta@Home, Folding@Home, World Community Grid, and more. Running 24/7 crunching for one of these great causes is a sure way to find holes in a system if there is truly some instability, unfortunately it takes a considerable amount of time to use them for stability testing so we use the list of programs below to all but guarantee the system to be 24/7 distributed computing stable:

• 8 threads of 32M SuperPi Mod 1.5 (ran at the same time using Hyper Pi 0.99b)
• 2 hours of 8 threads of Prime95 using Prime95 v25.7 Stress Testing Blend
• 2 hours of HCI MemTest Pro in Windows using all available memory
• 6 loops of 3DMark Vantage ran back to back

As mentioned, there are many schools of thought on stability testing, and that is ours. We certainly won't be presenting CPU-Z screen shots and saying the memory passed our benchmarks so we call it stable. Each overclock we are about to look at has passed a rigorous stability testing procedure. Just keep in mind these results are from a single sample of memory. Like some many things in life, when it comes to memory, there are no guarantees.

Let's be clear right from the start, there is nothing stock about running memory at DDR3-2133. Intel doesn't specify their processors to be able to run DDR3-2133, motherboards aren't specified to run DDR3-2133, the only component specified to run DDR3-2133 is the OCZ Blade PC3-17000 memory. Unfortunately, the memory is just 1/3 of the hardware needed to run memory. The motherboard plays a role and the most important component in this equation is the CPU. Yes, we were able to run the memory at the specified frequency and timings, with 1.65v...but only one of the three processors we tried could, and in the process a motherboard died trying to make another processor.

The screen shot above is our successful processor mounted in the EVGA X58 Classified. The Intel Xeon W3540 was the only processor capable of accomplishing the task of running our stability testing at the specified DDR3-2133 with 8-9-8-24 timings. Our incredible clocking i7 920 can not even run DDR3-2000 so it didn't stand a chance with these sticks, and when trying our i7 975 processor in the EVGA X58 3X SLI, we had to turn VTT up so high that the stock cooling couldn't handle it and we blew the VTT PWM on that board. Needless to say, DDR3-2133 isn't going to be 24/7 stable for a lot of users, we would go as far to say many users.

The stress on the memory controller, which is located on the CPU, is so great at DDR3-2133 that many CPU's will need either too high a VTT or simply won't be able to run 24/7. The reason for this insane amount of stress isn't just the memory frequency, but mostly due to the uncore frequency that needs to run to reach DDR3-2133. The uncore runs at a minimum 2x the memory frequency. At DDR3-2133, that means an extremely high uncore clock of 4266MHz is required. Getting a CPU that runs 4266MHz at ambient temperatures for 24/7 stability is going to likely require at least 1.50v VTT if not more, even if it is an exceptional CPU.

This is why you will see substantially higher memory overclocks with this memory in our Extreme Overclocking section. When running a single threaded benchmark or one that isn't near as demanding on the memory or the memory controller, these modules will run as high as you want them to pretty much. The below overclocks are going to be our 24/7 overclock results that pass our full stability testing methodology, and are 100% limited by the CPU.

If you have been reading the review up to this point, you will already understand that these overclocks are a product of our best CPU's memory controller, not so much the memory. Without a great CPU with a great memory controller on it, we wouldn't be able to run specified settings, let alone overclocked ones. Because of the limitations in memory clocking at this level by the CPU, we have to ask that you take the results with a grain of salt. No amount of volts or tweaking will accomplish these results with many i7 processors.

The results above are really quite an impressive set of stable results. Keep in mind, these aren't simple benchmark stable, these are full 24/7 stable overclocks. The 6-7-6 results are about the only ones that aren't being limited by the CPU and would scale with further vDIMM.

The 7-7-6 and 7-8-7 results are so close because the IMC finds both timing sets to be very similar both being CL7. Opening up CAS Latency to CL8 allowed us to clock the PC3-17000 OCZ Blade's up to their specified settings, but we simply couldn't get a single base clock higher stable. At 1070MHz, regardless of voltage Prime Blend would just gas out after a few minutes. So even though we were able to run the specified clocks and timings of this memory, we couldn't get a sliver more. Again indicating that we were very fortunate to get to the specified operating clocks of DDR3-2133. Below are the screen shots from the other three timing sets.

6-7-6 Stable Overclock click for full size... OCZ Blade @ 927 6-7-6-18 1T @ 1.754v under load

7-7-6 Stable Overclock click for full size... OCZ Blade @ 1035 7-7-6-20 1T @ 1.754v under load

7-8-7 Stable Overclock click for full size... OCZ Blade @ 1047 7-8-7-20 1T @ 1.754v vDIMM under load