memory
DDR
| Memory | Bandwidth |
|---|---|
| DDR “DDR 266 | 2.1 GB/s |
| DDR 333 | 2.6 GB/s |
| DDR 400 | 3.2 GB/s” |
| DDR2 533 | 4.2 GB/s |
| DDR2 667 | 5.3 GB/s |
| DDR2 800 | 6.4 GB/s” |
| DDR3 1066 | 8.5 GB/s |
| DDR3 1333 | 10.6 GB/s |
| DDR3 1600 | 12.8 GB/s |
| DDR3 1866 | 14.9 GB/s” |
| DDR4 2133 | 17 GB/s |
| DDR4 2400 | 19.2 GB/s |
| DDR4 2666 | 21.3 GB/s |
| DDR4 3200 | 25.6 GB/s” |
| DDR5 4800 | 38.4 GB/s |
| DDR5 5200 | 41.6 GB/s |
| DDR5 5400 | 43.2 GB/s |
| DDR5 5600 | 44.8 GB/s |
| DDR5 6000 | 48.0 GB/s |
| DDR5 6400 | 51.2 GB/s” |
LPDDR
AI-oriented smartphones face memory bandwidth bottlenecks, so they generally use the latest LPDDR technology.
SoCs based on the Qualcomm 8gen3 platform or MTK 9300 platform generally use LPDDR5X, namely 4800MHz LPDDR5 memory, with a rated memory bandwidth of 76.8GB/s and an actual bandwidth of up to 60GB/s.
SoCs based on the Qualcomm 8gen4 platform or MTK 9400 platform generally use LPDDR5X plus, namely 5333MHz LPDDR5 memory, with a rated memory bandwidth of 85.3GB/s and an actual bandwidth of up to xxGB/s.
In the LPDDR5 standard, one channel consists of 16 lines (differential pairs; the same applies below). Smartphones generally use 64 lines, or 4 channels. The data rate of a single line is 9600Mbps (corresponding to 4800MHz), and the total bandwidth is 9.6GT/s * 8 bytes/T = 76.8GB/s.
A single LPDDR6 line can reach 14.4Gbps, corresponding to a frequency of 7200MHz. One notable difference, however, is that one LPDDR6 channel consists of 24 lines, and 64 is not divisible by this number. A reasonable guess is that smartphones will use 2 channels (48 lines) or 3 channels (72 lines).
The total bandwidth should therefore be 14.4GT/s 6 bytes/T = 86.4GB/s or 14.4GT/s 9 bytes/T = 129.6 GB/s. In the latter case, the bandwidth is 1.69 times that of LPDDR5X and 1.51 times that of LPDDR5X plus.
UFS
The theoretical bandwidth of UFS 4 is 4GB/s. It has 2 lanes (differential wire pairs), and each differential wire pair runs at 23.2GT/s (the theoretical transfer rate excluding header overhead is 5.8GB/s).
Smartphones currently on the market generally use UFS 4.0. Storage access bandwidth depends on the medium and is also related to capacity (the number of internal banks). The fastest known actual speed is currently 3.8GB/s.
UFS 4.1 can theoretically reach 8GB/s; it is essentially a 4-lane version of UFS 4.
The JEDEC page for UFS is: https://www.jedec.org/sites/default/files/docs/JESD220.pdf
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