Memory timing examples
Generation | Type | Data rate | Bit time | Command rate | Cycle time | CL | First word | Fourth word | Eighth word |
---|---|---|---|---|---|---|---|---|---|
SDRAM | PC100 | 100 MT/s | 10 ns | 100 MHz | 10 ns | 2 | 20 ns | 50 ns | 90 ns |
PC133 | 133 MT/s | 7.5 ns | 133 MHz | 7.5 ns | 3 | 22.5 ns | 45 ns | 75 ns | |
DDR SDRAM | DDR-333 | 333 MT/s | 3 ns | 166 MHz | 6 ns | 2.5 | 15 ns | 24 ns | 36 ns |
DDR-400 | 400 MT/s | 2.5 ns | 200 MHz | 5 ns | 3 | 15 ns | 22.5 ns | 32.5 ns | |
2.5 | 12.5 ns | 20 ns | 30 ns | ||||||
2 | 10 ns | 17.5 ns | 27.5 ns | ||||||
DDR2 SDRAM | DDR2-667 | 667 MT/s | 1.5 ns | 333 MHz | 3 ns | 5 | 15 ns | 19.5 ns | 25.5 ns |
4 | 12 ns | 16.5 ns | 22.5 ns | ||||||
DDR2-800 | 800 MT/s | 1.25 ns | 400 MHz | 2.5 ns | 6 | 15 ns | 18.75 ns | 23.75 ns | |
5 | 12.5 ns | 16.25 ns | 21.25 ns | ||||||
4.5 | 11.25 ns | 15 ns | 20 ns | ||||||
4 | 10 ns | 13.75 ns | 18.75 ns | ||||||
DDR2-1066 | 1066 MT/s | 0.95 ns | 533 MHz | 1.9 ns | 7 | 13.13 ns | 15.94 ns | 19.69 ns | |
6 | 11.25 ns | 14.06 ns | 17.81 ns | ||||||
5 | 9.38 ns | 12.19 ns | 15.94 ns | ||||||
4.5 | 8.44 ns | 11.25 ns | 15 ns | ||||||
4 | 7.5 ns | 10.31 ns | 14.06 ns | ||||||
DDR3 SDRAM | DDR3-1066 | 1066 MT/s | 0.9375 ns | 533 MHz | 1.875 ns | 7 | 13.13 ns | 15.95 ns | 19.7 ns |
DDR3-1333 | 1333 MT/s | 0.75 ns | 666 MHz | 1.5 ns | 9 | 13.5 ns | 15.75 ns | 18.75 ns | |
6 | 9 ns | 11.25 ns | 14.25 ns | ||||||
DDR3-1375 | 1375 MT/s | 0.73 ns | 687 MHz | 1.5 ns | 5 | 7.27 ns | 9.45 ns | 12.36 ns | |
DDR3-1600 | 1600 MT/s | 0.625 ns | 800 MHz | 1.25 ns | 9 | 11.25 ns | 13.125 ns | 15.625 ns | |
8 | 10 ns | 11.875 ns | 14.375 ns | ||||||
7 | 8.75 ns | 10.625 ns | 13.125 ns | ||||||
6 | 7.50 ns | 9.375 ns | 11.875 ns | ||||||
DDR3-2000 | 2000 MT/s | 0.5 ns | 1000 MHz | 1 ns | 10 | 10 ns | 11.5 ns | 13.5 ns | |
9 | 9 ns | 10.5 ns | 12.5 ns | ||||||
8 | 8 ns | 9.5 ns | 11.5 ns | ||||||
7 | 7 ns | 8.5 ns | 10.5 ns |