X-Bitlabs have thrown a new article which looks at the advantages and shortcomings of the move from DDR to DDR2 memory technology! Here's a snip.
The next divergence between the memory types is in DDR2?s ability to do Variable Write Latency. DDR always has a write latency of 1T. This time is dictated by the specification and cannot be changed.
For DDR2, this write latency depends on the read latency and equals write latency minus one clock. For example, the read latency being 7 clocks, the write latency will be 6 clocks. This sounds terrible compared to 1 clock for DDR. In reality, it?s not that bad, because the write procedure with DDR requires some special preparation, unnecessary in DDR2. So there is a difference, but it is smaller than may seem. The resulting write latency of DDR2 is about three times higher than with DDR.
DDR vs. DDRII: Fight
The next divergence between the memory types is in DDR2?s ability to do Variable Write Latency. DDR always has a write latency of 1T. This time is dictated by the specification and cannot be changed.
For DDR2, this write latency depends on the read latency and equals write latency minus one clock. For example, the read latency being 7 clocks, the write latency will be 6 clocks. This sounds terrible compared to 1 clock for DDR. In reality, it?s not that bad, because the write procedure with DDR requires some special preparation, unnecessary in DDR2. So there is a difference, but it is smaller than may seem. The resulting write latency of DDR2 is about three times higher than with DDR.
DDR vs. DDRII: Fight
