There is talk that DDR2 memory is nearing the end of its life, and while this could be true to a certain extent, I believe it to be more of the opposite.
While DDR3 is on the horizon and will take memory frequencies well beyond 1GHz, from the time this memory is first released to the time it is adopted, that could still be well over a year from now. After all, DDR2 only properly replaced the original DDR memory last year, despite being released way back in 2004. Now that both AMD and Intel have converted all their platforms, sales of DDR2 memory are much stronger.
The official specification for a DDR2-800 memory module is 1.8 volts of power, and you are doing well if you can find any DDR2 modules that work perfectly in all systems using those settings. The fact is most DDR2-800 modules are just overclocked DDR2-667 modules. Therefore, in most instances users are better off purchasing PC2-5300/5400 (DDR2-667) memory, rather than the more expensive PC2-6400 (DDR2-800) memory, which in essence is the same thing. The only advantage in purchasing DDR2-800 memory in that case would be that it will operate at this frequency using the specified timings and voltage stated by the manufacturer.
Currently there is no shortage of memory modules that claim to work at 800MHz and beyond. For example, OCZ Technology offers a total of 9 memory kits that operate at 800MHz with 13 more that exceed this frequency. However, not one of these 800MHz kits uses just 1.8v, rather they all require at least 2.0v, with some requiring 2.2v or more. This is not such an issue if these modules can POST (Power On Self Test) at 1.8v, as the user can then enter the BIOS and make the necessary adjustments to improve stability. OCZ has gone a little crazy with DDR2 memory, creating 9 unique series. Perhaps one of the most intriguing are the bright red ATI CrossFire Certified memory modules.
These ATI CrossFire Certified memory modules were first announced last September 2006 and since then we have not heard or seen much from these. Other than the marketing spin put in the press release, there has been little information to go on. What we know is that these modules are designed and certified for CrossFire platforms by ATI, and that is about the bulk of it. So other than being 1GB DDR2-800 memory modules designed to operate in dual-channel mode at CAS4-4-4-12 with 2.1 volts, there is not a great deal more we can tell you. Everyone has been asking what is so special that makes these red modules more qualified to work with CrossFire platforms than the next DDR2-800 memory.
Well, we are asking the same question having tested the OCZ DDR2 PC2-6400 ATI CrossFire memory. In the past we have heard of modules creating compatibility issues with Nvidia SLI setups, though we never encountered such problems ourselves. That said, we have never once had a problem with memory compatibility when testing ATI's CrossFire technology. In fact, the only compatibility issues we have run into were due to the DDR2 memory modules not working with 1.8 or 1.9v settings, and instead requiring more power to POST. So never having encountered a single compatibility issue when testing CrossFire configurations in the past, are we qualified to test these memory modules?
As much as we do enjoy OCZ memory products, you have to question the need for these DDR2 PC2-6400 ATI CrossFire certified modules. The up side is they are one of the fastest DDR2-800 modules OCZ offers, though the timings (CAS4-4-4-12) are only marginally better than their other 800MHz offerings, and once again you will need to pump at least 2.1v through them to achieve 100% stability. Without any more time wasting, let's go and find out what these OCZ DDR2 PC2-6400 ATI CrossFire memory modules can do, and if they are in fact any different to existing DDR2-800 modules.