Everything You Need To Know About DDR, DDR2 and DDR3 Memories
Speeds
Contents
One of the main differences between DDR, DDR2 and DDR3 is the highest transfer rate each generation can reach. Below we list the most common speeds for each generation. Some manufacturers can deliver memory chips capable of achieving other speeds than those listed; for example, specialty memories targeted to overclockers. Clocks ending in 33 and 66 MHz are, in fact, periodic decimal expansions (33.3333 and 66.6666, respectively).
| Memory | Real Clock | Maximum Theoretical Transfer Rate | Memory Module |
| DDR200 | 100 MHz | 1,600 MB/s | PC-1600 |
| DDR266 | 133 MHz | 2,133 MB/s | PC-2100 |
| DDR333 | 166 MHz | 2,666 MB/s | PC-2700 |
| DDR400 | 200 MHz | 3,200 MB/s | PC-3200 |
| DDR2-400 | 200 MHz | 3,200 MB/s | PC2-3200 |
| DDR2-533 | 266 MHz | 4,266 MB/s | PC2-4200 |
| DDR2-667 | 333 MHz | 5,333 MB/s | PC2-5300 |
| DDR2-800 | 400 MHz | 6,400 MB/s | PC2-6400 |
| DDR2-1066 | 533 MHz | 8,533 MB/s | PC2-8500 |
| DDR3-800 | 400 MHz | 6,400 MB/s | PC3-6400 |
| DDR3-1066 | 533 MHz | 8,500 MB/s | PC3-8500 |
| DDR3-1333 | 666 MHz | 10,666 MB/s | PC3-10600 |
| DDR3-1600 | 800 MHz | 12,800 MB/s | PC3-12800 |