The spec for DDR2-1066 (PC2-8500) is 1.8v. Applying a greater voltage to achieve the spec is over-clocking, whether it's tested or not. Again, reports of the Crucial parts failing are rampant on the net. This isn't an isolated case with my system. These parts are being pushed above their nominal operating parameters to achieve the specs of higher quality parts.

CPUs and GPUs are often binned down, but that's just about the reverse of what we're seeing with the memory we're discussing. That is, when a part doesn't pass testing at its designed clock rates, it is rebadged or relabeled and clocked lower while being sold at a lower price point. Same goes for blown transistors and pipes, etc. Case in point, AMD's 3-core chips and more Radeon products than I can count.

It does appear this over-spec clocking is the case with most memory (of this type) out there right now. A search on NewEgg for DDR2-1066 at 1.8v yields only two products. There's a large selection of DDR2-800 at 1.8v. The Ballistix are overclocked DDR2-800 parts and nothing more.