MMC/SD/SDHC card library: Benchmarks
The following results show some benchmarks done with the sd-reader library. Please note that results vary greatly depending on the card being used. Also note that read rates do not include the processing of the data being read, the same applies to write rates and the generation of the data being written. So for a real application, data rates may be (much) lower.
FAT16
| Read release 20090330 |
Write release 20090330 preallocated |
Write release 20090330 enlarging |
Write release 20100110 enlarging, delayed dir updates |
|||||
|---|---|---|---|---|---|---|---|---|
| Chunk size (Bytes) | Time (s) | Data rate (kB/s) | Time (s) | Data rate (kB/s) | Time (s) | Data rate (kB/s) | Time (s) | Data rate (kB/s) |
| 2048 | 10.0 | 204.8 | 10.5 | 195.0 | 91.0 | 22.5 | 70 | 29.3 |
| 1024 | 10.0 | 204.8 | 10.5 | 195.0 | 125.0 | 16.4 | 70 | 29.3 |
| 512 | 10.0 | 204.8 | 11.0 | 186.2 | 197.0 | 10.4 | 70 | 29.3 |
| 256 | 10.5 | 195.0 | 19.5 | 105.0 | 363.0 | 5.6 | 78.5 | 26.1 |
| 128 | 10.5 | 195.0 | 20.0 | 102.4 | 669.0 | 3.1 | 79 | 25.9 |
| 64 | 11.5 | 178.1 | 20.5 | 99.9 | 1244.0 | 1.6 | 79.5 | 25.8 |
| 32 | 12.5 | 163.8 | 22.0 | 93.1 | 80 | 25.6 | ||
| 16 | 15.0 | 136.5 | 24.5 | 83.6 | 82.5 | 24.8 | ||
| 8 | 20.0 | 102.4 | 29.5 | 69.4 | 89 | 23.0 | ||
Test conditions: ATmega128 at 14.745 MHz, 128 MB SD card, FAT16-only configuration, 2 MB file, buffered access, without timestamps.
FAT32
| Read release 20090330 |
Write release 20090330 preallocated |
Write release 20090330 enlarging |
Write release 20100110 enlarging, delayed dir updates |
|||||
|---|---|---|---|---|---|---|---|---|
| Chunk size (Bytes) | Time (s) | Data rate (kB/s) | Time (s) | Data rate (kB/s) | Time (s) | Data rate (kB/s) | Time (s) | Data rate (kB/s) |
| 2048 | 8.5 | 240.9 | 17.5 | 117.0 | 43.0 | 47.6 | 28.0 | 73.1 |
| 1024 | 8.5 | 240.9 | 17.5 | 117.0 | 51.0 | 40.2 | 28.0 | 73.1 |
| 512 | 9.0 | 227.6 | 18.0 | 113.8 | 65.0 | 31.5 | 28.0 | 73.1 |
| 256 | 9.5 | 215.6 | 26.5 | 77.3 | 124.0 | 16.5 | 36.5 | 56.1 |
| 128 | 10.5 | 195.0 | 27.5 | 74.5 | 229.0 | 8.9 | 37.5 | 54.6 |
| 64 | 13.0 | 157.5 | 30.0 | 68.3 | 432.0 | 4.7 | 40.0 | 51.2 |
| 32 | 18.0 | 113.8 | 34.5 | 59.4 | 44.5 | 46.0 | ||
| 16 | 27.5 | 74.5 | 43.5 | 47.1 | 54.0 | 37.9 | ||
| 8 | 47.0 | 43.6 | 62.5 | 32.8 | 73.0 | 28.1 | ||
Test conditions: ATmega128 at 14.745 MHz, 4 GB SDHC card, FAT32, 2 MB file, buffered access, without timestamps.