# SanDisk Extreme 64GB
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=500K count=1024; time sync
1024+0 records in
1024+0 records out
524288000 bytes (524 MB) copied, 24.9729 s, 21.0 MB/s

real    0m25.027s
user    0m0.000s
sys     0m6.150s

real    0m3.757s
user    0m0.020s
sys     0m0.020s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=500K count=1024
1024+0 records in
1024+0 records out
524288000 bytes (524 MB) copied, 1.10928 s, 473 MB/s
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=50K count=1024; time sync
1024+0 records in
1024+0 records out
52428800 bytes (52 MB) copied, 0.653916 s, 80.2 MB/s

real    0m1.506s
user    0m0.010s
sys     0m1.490s

real    0m2.714s
user    0m0.000s
sys     0m0.030s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=50K count=1024
1024+0 records in
1024+0 records out
52428800 bytes (52 MB) copied, 0.114238 s, 459 MB/s
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=4K count=1024; time sync
1024+0 records in
1024+0 records out
4194304 bytes (4.2 MB) copied, 0.0601847 s, 69.7 MB/s

real    0m0.081s
user    0m0.000s
sys     0m0.070s

real    0m0.242s
user    0m0.010s
sys     0m0.010s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=4K count=1024
1024+0 records in
1024+0 records out
4194304 bytes (4.2 MB) copied, 0.0120316 s, 349 MB/s
# SanDisk Ultra 32GB
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=500K count=1024; time sync
1024+0 records in
1024+0 records out
524288000 bytes (524 MB) copied, 33.7319 s, 15.5 MB/s

real    0m33.744s
user    0m0.020s
sys     0m6.130s

real    0m7.454s
user    0m0.000s
sys     0m0.040s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=500K count=1024
1024+0 records in
1024+0 records out
524288000 bytes (524 MB) copied, 1.26001 s, 416 MB/s
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=50K count=1024; time sync
1024+0 records in
1024+0 records out
52428800 bytes (52 MB) copied, 0.655562 s, 80.0 MB/s

real    0m1.508s
user    0m0.000s
sys     0m1.500s

real    0m3.413s
user    0m0.000s
sys     0m0.030s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=50K count=1024
1024+0 records in
1024+0 records out
52428800 bytes (52 MB) copied, 0.128287 s, 409 MB/s
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=4K count=1024; time sync
1024+0 records in
1024+0 records out
4194304 bytes (4.2 MB) copied, 0.0608661 s, 68.9 MB/s

real    0m0.156s
user    0m0.010s
sys     0m0.140s

real    0m0.293s
user    0m0.000s
sys     0m0.010s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=4K count=1024
1024+0 records in
1024+0 records out
4194304 bytes (4.2 MB) copied, 0.0121033 s, 347 MB/s
# Samsung Pro 32GB
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=500K count=1024; time sync                                                                                                                                                      time sync
1024+0 records in
1024+0 records out
524288000 bytes (524 MB) copied, 20.6546 s, 25.4 MB/s

real    0m20.667s
user    0m0.030s
sys     0m5.920s

real    0m8.886s
user    0m0.000s
sys     0m0.050s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=500K count=1024
1024+0 records in
1024+0 records out
524288000 bytes (524 MB) copied, 1.25766 s, 417 MB/s
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=50K count=1024; time sync                                                                                                                                                            ime sync
1024+0 records in
1024+0 records out
52428800 bytes (52 MB) copied, 0.652953 s, 80.3 MB/s

real    0m1.504s
user    0m0.030s
sys     0m1.470s

real    0m3.251s
user    0m0.000s
sys     0m0.070s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=50K count=1024
1024+0 records in
1024+0 records out
52428800 bytes (52 MB) copied, 0.130543 s, 402 MB/s
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=4K count=1024; time sync                                                                                                                                                             me sync
1024+0 records in
1024+0 records out
4194304 bytes (4.2 MB) copied, 0.0608279 s, 69.0 MB/s

real    0m0.157s
user    0m0.010s
sys     0m0.140s

real    0m0.270s
user    0m0.010s
sys     0m0.010s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=4K count=1024
1024+0 records in
1024+0 records out
4194304 bytes (4.2 MB) copied, 0.0136807 s, 307 MB/s
# No Name 32GB
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=500K count=1024; time sync                                                                                                                                                             time sync
1024+0 records in
1024+0 records out
524288000 bytes (524 MB) copied, 54.6691 s, 9.6 MB/s

real    0m54.681s
user    0m0.030s
sys     0m5.950s

real    0m20.851s
user    0m0.000s
sys     0m0.040s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=500K count=1024
1024+0 records in
1024+0 records out
524288000 bytes (524 MB) copied, 1.2603 s, 416 MB/s
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=50K count=1024; time sync                                                                                                                                                            ime sync
1024+0 records in
1024+0 records out
52428800 bytes (52 MB) copied, 0.642695 s, 81.6 MB/s

real    0m1.485s
user    0m0.000s
sys     0m1.480s

real    0m7.096s
user    0m0.010s
sys     0m0.020s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=50K count=1024
1024+0 records in
1024+0 records out
52428800 bytes (52 MB) copied, 0.127583 s, 411 MB/s
pi@raspberrypi ~ $ sync; time dd if=/dev/zero of=~/test.tmp bs=4K count=1024; time sync                                                                                                                                                          me sync
1024+0 records in
1024+0 records out
4194304 bytes (4.2 MB) copied, 0.0604193 s, 69.4 MB/s

real    0m0.156s
user    0m0.000s
sys     0m0.150s

real    0m0.590s
user    0m0.010s
sys     0m0.000s
pi@raspberrypi ~ $ dd if=~/test.tmp of=/dev/null bs=4K count=1024
1024+0 records in
1024+0 records out
4194304 bytes (4.2 MB) copied, 0.0132791 s, 316 MB/s