Overview Of DDR Vs. DDR2
Source : Micron DesignLine Vol. 12, 3Q03
DDR2 : Speed
More interesting than the potential clock speeds are the bandwidths in dual channel operation that result from them (far right column) :
| Memory Type | Clock Speed | Name | BandwidthSingle-Channel | BandwidthDual-Channel |
|---|---|---|---|---|
| DDR266 | 133 MHz DDR | PC2100 | 2,100 MB/s | 4,200 MB/s |
| DDR333 | 166 MHz DDR | PC2700 | 2,700 MB/s | 5,400 MB/s |
| DDR400 | 200 MHz DDR | PC3200 | 3,200 MB/s | 6,400 MB/s |
| DDR2 400 | 200 MHz DDR | PC2 3200* | 3,200 MB/s | 6,400 MB/s |
| DDR2 533 | 266 MHz DDR | PC2 4300* | 4,266 MB/s | 8,533 MB/s |
| DDR2 667 | 333 MHz DDR | PC2 5300* | 5,333 MB/s | 10,666 MB/s |
| DDR2 800 | 400 MHz DDR | PC2 6400* | 6,400 MB/s | 12,800 MB/s |
* Source : Corsair website
8,533 MB/s (8.33 GB/s) in dual-channel operation is what we get with DDR2 533 - and this in itself sounds promising. However, there are two major factors that will fundamentally reduce the extra performance potential : firstly, the timings that have been possible up to now with CL 4 and 4-4-12 can still be increased ; secondly, at 533 MHz in the DDR process, the memory has to be run pseudo-synchronously to the 800 MHz FSB of the P4 (quad-data rate process) at a ratio of 2:3 - in the past, this has often proven to be an effort made in vain.
