It is fair to ask which is better, the Corsair 6400C3 or the OCZ Ti Alpha PC2-8000? The answer depends on what you are looking for. Performance on both of these top memories is all but identical, and it is equally outstanding. We have to look elsewhere for differences. We find that difference in voltage requirements. The Corsair 6400C3 requires less voltage at almost every speed to reach the same performance level. In fact the Corsair generally requires less voltage at each speed than any of our previously tested High-performance DDR2. Some will see this as a great advantage for Corsair 6400C3 and we would agree.
The other side of the coin is the fact that OCZ binned their VX2 memory for higher voltages, and the fact that a bit more voltage is required at each speed should not be a surprise. Offsetting this is the reassurance from OCZ than you can run their VX2 memory up to 2.525V without affecting your Lifetime Warranty. We could find no case in our testing where higher voltage on VX2 gave us more performance than the Corsair, but we were testing with air cooling and an extra fan. Those who can cool their memory with more effective solutions may find they can squeeze a bit more performance from the OCZ VX2.
It is remarkable to us that Corsair and OCZ took such different approaches when using the same Micron memory chips and yet ended up with such similar performance. The Corsair CM2X1024 6400C3 and the OCZ Ti Alpha PC2-8000 VX2 are currently at the top of the DDR2 performance pyramid. Either can provide results that is the best available in DDR2. Beyond that you will need to compare price and how you will use the memory to reach a decision between the two. Neither of these stellar performers is a good choice in an average system as they are both far too expensive to deliver good value. However, if you demand the best, either of these top-performing memories will deliver the goods.
Source:Corsair and OCZ: New Standards in Fast DDR2