The latency hit from DDR2 is harsher then that seen on high-latency DDR. There will be no benefit noticed from PC2-3200 or PC2-4300 by anyone with a standard system. Since there is no DDR2 and i915-motherboards on the market, there’s no way for the majority of us to note average yield rates for 3.75ns DDR2-533 chips. Usually, when something is new, it’s yields rather poorly. And from what OCZ's forum-scroungers (
) have been saying, early DDR2 doesn't seem to be yielding any better then current 5ns and 4ns DDR chips. This goes to say that DDR2 will not be much of an issue for this year.
Like many things, DDR2 will likely yield better with each new shipment, and we may be seeing high-yielding 3ns DDR2-667 once it becomes mature in the marketplace. DDR2-667 is expected to reach mass production around Q2 2005, so it may be some time after that before DDR2-667 would reach maturity similar to that found in DDR memory. It is likely that not until this time, which is reaching further in the 2nd Half of 2005, AMD will choose to implement DDR2 support into it’s Socket 939 processors. Motherboards would then enter the market, say around Q4 2005 or later, that have 240-pin DDR2 DIMMs, and perhaps some will come with mixed DDR2/DDR DIMMs. So we may be seeing DDR2 coming into it’s own, but it is possible that it will not be likely until we enter 2006.
For now, this is mostly speculation, but there is not much else to do on the matter.
Latency Table – For Reference
PC-3200 (DDR-400) - 2-2-2 (10ns)
PC-3700 (DDR-466) - 2.5-3-2 (11ns-13ns-8.5ns)
PC-4000 (DDR-500) - 3-3-3 (12ns)
PC-4600 (DDR-570) - 3-4-4 (10.5ns-14ns)
PC-4800 (DDR-600) - 3-4-4 (10ns-12ns)
PC2-3200 (DDR2-400) - 3-3-3 (15ns)
PC2-4300 (DDR2-533) - 4-4-4 (15ns)
PC2-5300 (DDR2-667) - 5-5-5 (15ns)
PC2-6400 (DDR2-800) - 6-6-6 (15ns)
