MMC/SD Card Throughput¶

Below are test results using a L138-FG-225-RC module.

The instructions found here (http://support.criticallink.com/redmine/projects/arm9-platforms/wiki/Setting_CPU_Speed) were followed to change the CPU clock frequency for each test.

The Class 10 Card was a PNY Professional 8GB SD Card.
The Class 4 Card was a Kingston 4GB MicroSD Card in a full size SD card adapter.

Each test was performed at 300MHz, 372MHz and 456MHz on the same development kit PCB with the same SoM. The tests were performed using the linux 'dd' utility. However note that the tests were performed without respect to a particular filesystem type (I.e. FAT, EXT2, etc.) so these speeds are best case and will be slower when writing to a file system.

Write Speed Tests¶

Class 10 Linux PC Write Speed = 13.X MB/s
Class 4 Linux PC Write Speed = 5.X MB/s

300MHz¶

Class 10 SD Card

time sh -c "dd if=/dev/zero of=/dev/mmcblk0p1 bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 73.0217 s, 9.2 MB/s
real    1m 13.17s
user    0m 0.15s
sys     0m 14.21s

Class 4 SD Card

time sh -c "dd if=/dev/zero of=/dev/mmcblk0p1 bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 127.457 s, 5.3 MB/s
real    2m 7.61s
user    0m 0.14s
sys     0m 15.20s

372MHz¶

Class 10 SD Card

time sh -c "dd if=/dev/zero of=/dev/mmcblk0p1 bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 64.2673 s, 10.4 MB/s
real    1m 4.43s
user    0m 0.08s
sys     0m 12.36s

Class 4 SD Card

time sh -c "dd if=/dev/zero of=/dev/mmcblk0p1 bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 125.338 s, 5.4 MB/s
real    2m 5.47s
user    0m 0.16s
sys     0m 13.80s

456MHz¶

Class 10 SD Card

time sh -c "dd if=/dev/zero of=/dev/mmcblk0p1 bs=64k count=10240 &&
 sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 67.4358 s, 10.0 MB/s
real    1m 7.52s
user    0m 0.13s
sys     0m 10.80s

Class 4 SD Card

time sh -c "dd if=/dev/zero of=/dev/mmcblk0p1 bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 122.894 s, 5.5 MB/s
real    2m 2.99s
user    0m 0.16s
sys     0m 13.33s

Read Speed Tests¶

Class 10 Linux PC Read Speed = 19.X MB/s
Class 4 Linux PC Read Speed = 18.X MB/s

300MHz¶

Class 10 SD Card

time sh -c "dd of=/dev/null if=/dev/mmcblk0p1 bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 48.3621 s, 13.9 MB/s
real    0m 48.47s
user    0m 0.18s
sys     0m 20.13s

Class 4 SD Card

time sh -c "dd of=/dev/null if=/dev/mmcblk0p1 bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 51.963 s, 12.9 MB/s
real    0m 52.17s
user    0m 0.29s
sys     0m 21.40s

372MHz¶

Class 10 SD Card

time sh -c "dd of=/dev/null if=/dev/mmcblk0p1 bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 45.9785 s, 14.6 MB/s
real    0m 46.06s
user    0m 0.13s
sys     0m 10.29s

Class 4 SD Card

time sh -c "dd of=/dev/null if=/dev/mmcblk0p1 bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 44.5213 s, 15.1 MB/s
real    0m 44.60s
user    0m 0.21s
sys     0m 15.75s

456MHz¶

Class 10 SD Card

time sh -c "dd of=/dev/null if=/dev/mmcblk0p1 bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 46.1925 s, 14.5 MB/s
real    0m 46.26s
user    0m 0.08s
sys     0m 16.34s

Class 4 SD Card

time sh -c "dd of=/dev/null if=/dev/mmcblk0p1 bs=64k count=10240 && sync" 
10240+0 records in
10240+0 records out
671088640 bytes (671 MB) copied, 49.8998 s, 13.4 MB/s
real    0m 49.97s
user    0m 0.12s
sys     0m 15.15s