Came with my BeagleBoard-xM purchased near the end of 2010. Card was previously used extensively. Repartitioned to be aligned to 4MiB before testing.

# BeagleBoard-xM is my only home computer with a built-in MMC device:

root@192:~/flashbench# head /sys/block/mmcblk0/device/* 2>/dev/null | grep -v ^$ ==> /sys/block/mmcblk0/device/block <== ==> /sys/block/mmcblk0/device/cid <== 02544d5341303447061111058e00aaf1 ==> /sys/block/mmcblk0/device/csd <== 400e00325b5900001d6f7f800a4000a1 ==> /sys/block/mmcblk0/device/date <== 10/2010 ==> /sys/block/mmcblk0/device/driver <== ==> /sys/block/mmcblk0/device/erase_size <== 512 ==> /sys/block/mmcblk0/device/fwrev <== 0x6 ==> /sys/block/mmcblk0/device/hwrev <== 0x0 ==> /sys/block/mmcblk0/device/manfid <== 0x000002 ==> /sys/block/mmcblk0/device/name <== SA04G ==> /sys/block/mmcblk0/device/oemid <== 0x544d ==> /sys/block/mmcblk0/device/power <== ==> /sys/block/mmcblk0/device/preferred_erase_size <== 4194304 ==> /sys/block/mmcblk0/device/scr <== 0235800001000000 ==> /sys/block/mmcblk0/device/serial <== 0x1111058e ==> /sys/block/mmcblk0/device/subsystem <== ==> /sys/block/mmcblk0/device/type <== SD ==> /sys/block/mmcblk0/device/uevent <== DRIVER=mmcblk MMC_TYPE=SD MMC_NAME=SA04G MODALIAS=mmc:block

# All further tests done using Transcend USB2.0 reader

andrew@bigbox:~/flashbench$ sudo sfdisk -uS -l /dev/sdc

Disk /dev/sdc: 1884 cylinders, 128 heads, 32 sectors/track Units = sectors of 512 bytes, counting from 0

Device Boot Start End #sectors Id System /dev/sdc1 * 8192 7716863 7708672 c W95 FAT32 (LBA) /dev/sdc2 0 - 0 0 Empty /dev/sdc3 0 - 0 0 Empty /dev/sdc4 0 - 0 0 Empty

andrew@bigbox:~/flashbench$ sudo ./flashbench -a /dev/sdc --blocksize=1024 --count=100 align 1073741824 pre 2.06ms on 3.41ms post 2.24ms diff 1.26ms align 536870912 pre 2.09ms on 3.48ms post 2.31ms diff 1.28ms align 268435456 pre 2.09ms on 3.42ms post 2.27ms diff 1.24ms align 134217728 pre 2.09ms on 3.44ms post 2.26ms diff 1.27ms align 67108864 pre 1.94ms on 3.26ms post 2.25ms diff 1.17ms align 33554432 pre 2.07ms on 3.4ms post 2.24ms diff 1.25ms align 16777216 pre 2.04ms on 3.41ms post 2.24ms diff 1.27ms align 8388608 pre 1.9ms on 3.26ms post 2.24ms diff 1.19ms align 4194304 pre 1.93ms on 3.09ms post 2.07ms diff 1.09ms align 2097152 pre 2.06ms on 2.08ms post 2.05ms diff 25.4µs align 1048576 pre 2.08ms on 2.11ms post 2.08ms diff 32.4µs align 524288 pre 2.06ms on 2.09ms post 2.05ms diff 32.2µs align 262144 pre 2.06ms on 2.08ms post 2.07ms diff 21.5µs align 131072 pre 2.06ms on 2.09ms post 2.06ms diff 24.9µs align 65536 pre 2.07ms on 2.08ms post 2.06ms diff 14µs align 32768 pre 2.06ms on 2.09ms post 2.07ms diff 23.8µs align 16384 pre 2.06ms on 2.09ms post 2.06ms diff 32µs align 8192 pre 2.06ms on 2.08ms post 2.07ms diff 17.9µs align 4096 pre 2.05ms on 2.06ms post 2.07ms diff -7783ns align 2048 pre 2.07ms on 2.07ms post 2.07ms diff -4929ns

# 4MiB erase block # 8KiB page

andrew@bigbox:~/flashbench$ sudo ./flashbench /dev/sdc --open-au --erasesize=$[4*1024*1024] --blocksize=$[4*1024] --open-au-nr=1 4MiB 3.57M/s 2MiB 4.76M/s 1MiB 4.75M/s 512KiB 4.87M/s 256KiB 4.75M/s 128KiB 4.63M/s 64KiB 4.71M/s 32KiB 4.67M/s 16KiB 4.75M/s 8KiB 4.38M/s 4KiB 3.78M/s andrew@bigbox:~/flashbench$ sudo ./flashbench /dev/sdc --open-au --erasesize=$[4*1024*1024] --blocksize=$[4*1024] --open-au-nr=2 4MiB 4.72M/s 2MiB 2.81M/s 1MiB 1.43M/s 512KiB 730K/s 256KiB 369K/s 128KiB 187K/s 64KiB 94.3K/s 32KiB 47.3K/s 16KiB 23.7K/s 8KiB 12K/s 4KiB 6.05K/s

## Only can have one open page at a time

andrew@bigbox:~/flashbench$ sudo ./flashbench /dev/sdc --open-au --erasesi*1024*1024] --blocksize=$[4*1024] --open-au-nr=1 --random 4MiB 3.45M/s 2MiB 3.22M/s 1MiB 2.87M/s 512KiB 1.15M/s 256KiB 453K/s 128KiB 280K/s 64KiB 142K/s 32KiB 77.7K/s 16KiB 38.4K/s 8KiB 19.5K/s 4KiB 9.79K/s

## Generally horrible at random

andrew@bigbox:~/flashbench$ sudo ./flashbench --findfat --fat-nr=6 /dev/sdc --blocksize=$[8*1024] --random 4MiB 5.27M/s 2.77M/s 3.32M/s 4.81M/s 4.75M/s 4.7M/s 2MiB 4.48M/s 3.05M/s 1.53M/s 2.57M/s 2.63M/s 2.64M/s 1MiB 3.94M/s 3.39M/s 1.89M/s 1.79M/s 1.8M/s 1.78M/s 512KiB 2.59M/s 2.93M/s 943K/s 929K/s 930K/s 934K/s 256KiB 3.58M/s 3.4M/s 554K/s 556K/s 557K/s 556K/s 128KiB 1.64M/s 2.33M/s 249K/s 271K/s 271K/s 259K/s 64KiB 1.54M/s 1.56M/s 134K/s 134K/s 134K/s 134K/s 32KiB 751K/s 982K/s 74K/s 74.1K/s 74.2K/s 74.2K/s