SPD of our today’s heroes contains the following information:
The funny thing is that Crucial didn’t encode into the SPD the manufacturer’s name as well as the product part number. According to the SPD, these memory modules can only work at 1GHz frequency with the timings set to their nominal values of 5-5-5-15.
Unfortunately, the fact that there is only overclocking friendly work mode listed in the SPD causes some compatibility issues. Far not all the mainboards out there can interpret the 1000MHz memory working frequency correctly, so that some of them may simply refuse to work at all. For example, we could pass the POST on our ASUS P5ND2-SLI Deluxe based on NVIDIA nForce4 SLI (Intel Edition). Our memory modules would only work on this mainboard if the frequency and timings were set manually. In this case, however, you need another set of DIMM modules to start the system with default parameters first.
The memory chips used in Crucial Ballistix PC2-8000 memory modules are made by Micron, which is actually not at all surprising. Namely these are MT47H64M8BT-3:A chips. According to the specification, these memory chips are designed to work at 667MHz frequency with CL=5. How does Crucial manage to make these chips work at 50% higher frequency than their nominal value? The answer to this question is quite obvious: it is possible due to extremely high voltage.
The nominal voltage for almost any DDR2 SDRAM chips equals 1.8V. This is one of the DDR2 standard requirements approved by the JEDEC committee. Crucial declared the nominal voltage of 2.2V for their Ballistix PC2-8000 series, which is 22% higher than the standard. This voltage increase allows to significantly improve other technical characteristics. In this case it would be quite natural for you to have some concerns about the reliability of these memory modules if they are working at significantly increased voltage for a long time. However, I have to assure you that you should forget all your worries in this respect. Firstly, the manufacturer took good care of the additional heat dissipation, and secondly, there is life-time warranty for this memory. So, Crucial Ballistix PC2-8000 is very unlikely to break down, and if something still happens to these modules, you will get replacement immediately.