We had two goals with our review: first, to see if this memory kit could really run at 1,150 MHz. Second, to see the maximum clock rate we could put this kit to work keeping its labeled timings (5-5-5-12).
Of course when working at a higher clock rate the memory is capable of delivering a higher transfer rate, as the transfer rate is directly proportional to the clock used (transfer rate = number of bits x clock rate / 8). In our review, however, we were not interested in learning what is the maximum transfer rate achieved by these memory modules, since this memory kit is targeted to people that want to achieve a higher clock rate with their CPUs – a higher transfer rate is a consequence.
For our review we used an nForce 680i-based motherboard (ECS PN2 SLI2+) and a Core 2 Duo E6700 CPU. This motherboard has a separated clock generator for the memory, so we could increase the memory clock without increasing the CPU clock, which is terrific to evaluate this kind of memory – since the CPU won’t be overclocked only the memory modules will limit the maximum clock rate we will achieve.
We could set this kit to run at 1,150 MHz with their nominal 5-5-5-12 timings without sweat. So they deliver what the manufacturer is saying they are capable of.
Then we decided to see what was the maximum clock rate these memories could run maintaining their 5-5-5-12 timings (if you increase timings usually you can achieve higher clock rates but lowering memory performance) and voltage (2.3 V). We could set them up to 1,219 MHz (609.5 MHz x2) as you can see in Figure 5 (on setup the memory clock was set as 1,244 MHz, but let’s consider the clock as read by CPU-Z), 153 MHz more than their nominal rating.
We could set them above 1,244 MHz but the system didn’t pass our stability test. So we decided to increase the memory voltage to 2.4 V to see what happened and with this new voltage we were able to put the memories running at 1,280 MHz (640 MHz x 2) as you can see in Figure 6. This is 214 MHz over DDR2-1066 standard clock rate.
An important thing we discovered during our tests is that you have to set the memory voltage manually at the motherboard setup or you won’t achieve the full potential of this product. We forgot to set this voltage and the maximum clock rate we could achieve was 1,150 MHz, as the system fed the memories with 1.85 V instead of 2.3 V.