I recently bought a number of high end MicroSD cards for SDIO tests on fast STM32 micros. Performance with 4-bit SDIO is great, read/write at over 20 MB/sec is possible.
I decided to benchmark these cards on an Uno. Performance is limited since these cards were not designed for SPI.
Here is a long list of benchmarks. Each test has 10 reps of writing a 5 MB file and five reps of reading a 5 MB file. The biggest difference is write speed and maximum write latency.
First let me warn you that there are many fake cards floating around. The first result is a fake SanDisk 8 GB Ultra sold on Amazon by Nano-Real www.amazon.com/gp/product/B0085EG6OW.
Note the slow, 76 KB/sec, write speed and long , over 140 ms, max write latency.
Fake 8 GB Ultra
Type is FAT32
Card size: 7.99 GB (GB = 1E9 bytes)Manufacturer ID: 0X12
OEM ID: 4V
Product: MS
Version: 0.0
Serial number: 0XE1480000
Manufacturing date: 5/2014File size 5 MB
Buffer size 512 byteswrite speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
75.86,144628,2472,6741
76.34,142692,4740,6698
76.36,142648,4732,6697
76.33,142756,4732,6699
76.20,148644,4732,6711
76.37,142544,4728,6695
76.39,142628,4736,6694
76.43,142504,4724,6690
76.31,142584,4728,6701
76.44,142612,4728,6690read speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
341.44,2332,1164,1493
341.44,2324,1164,1493
341.44,2332,1164,1493
341.46,2336,1164,1493
341.44,2332,1164,1494
Here is a real SanDisk 16 GB Ultra http://www.amazon.com/gp/product/B007XZM6VG. Much better.
16 GB SanDisk Ultra
Type is FAT32
Card size: 15.93 GB (GB = 1E9 bytes)Manufacturer ID: 0X3
OEM ID: SD
Product: SL16G
Version: 8.0
Serial number: 0XFC434325
Manufacturing date: 4/2014File size 5 MB
Buffer size 512 byteswrite speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
251.28,22896,1696,2031
250.98,20788,1696,2034
250.61,32348,1696,2037
251.15,20412,1684,2032
250.76,20664,1700,2035
251.30,20036,1696,2031
251.01,19960,1696,2032
251.48,20056,1664,2030
251.24,20736,1672,2032
250.92,20160,1696,2034read speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
500.07,2028,1000,1018
500.17,2024,1000,1018
500.12,2028,1000,1018
500.02,2020,996,1018
500.07,2020,1000,1018
Here is a strange result, the 32 GB version is not very good for write latency on SPI but OK on STM32 with SDIO http://www.amazon.com/gp/product/B007XZM6VG.
SanDisk 32 GB Ultra
Type is FAT32
Card size: 31.91 GB (GB = 1E9 bytes)Manufacturer ID: 0X3
OEM ID: SD
Product: SL32G
Version: 8.0
Serial number: 0XC2E6F10D
Manufacturing date: 6/2014File size 5 MB
Buffer size 512 byteswrite speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
241.93,75572,1608,2110
246.17,69084,1620,2073
242.12,79292,1624,2108
245.67,76168,1620,2078
243.48,85104,1620,2096
241.57,63892,1624,2113
244.10,78440,1616,2091
244.94,70436,1624,2084
239.76,90892,1624,2129
243.35,82420,1620,2097read speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
480.74,2428,1044,1059
480.74,2420,1044,1059
480.78,2424,1044,1059
480.78,2428,1044,1059
480.83,2428,1044,1059
Here is the 16 GB SanDisk Extreme http://www.amazon.com/gp/product/B00FRHTXR2. Very good max write latency.
SanDisk 16 GB Extreme
Type is FAT32
Card size: 15.93 GB (GB = 1E9 bytes)Manufacturer ID: 0X3
OEM ID: SD
Product: SE16G
Version: 8.0
Serial number: 0X3752B221
Manufacturing date: 10/2013File size 5 MB
Buffer size 512 byteswrite speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
287.22,10724,1484,1776
296.38,10556,1592,1721
295.38,10552,1624,1727
295.14,10556,1588,1729
295.16,10564,1624,1728
295.28,10564,1624,1728
295.25,10548,1588,1728
295.28,10568,1624,1728
295.30,10552,1584,1728
295.07,10544,1624,1729read speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
495.41,2036,1004,1027
495.46,2032,1004,1027
495.46,2020,1004,1027
495.56,2020,1004,1027
495.46,2032,1004,1027
The SanDisk 32 GB Extreme is also good http://www.amazon.com/gp/product/B00FRHTXR2.
SandDisk 32 GB Extreme
Type is FAT32
Card size: 31.91 GB (GB = 1E9 bytes)Manufacturer ID: 0X3
OEM ID: SD
Product: SE32G
Version: 8.0
Serial number: 0XF6D24F1
Manufacturing date: 5/2014File size 5 MB
Buffer size 512 byteswrite speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
282.76,10768,1504,1805
292.53,10624,1644,1744
292.28,10596,1648,1746
292.45,10332,1644,1744
292.05,10588,1608,1747
292.50,10600,1648,1744
292.29,10628,1648,1745
292.34,10604,1644,1745
292.46,10604,1648,1744
292.46,10612,1608,1744read speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
487.54,2060,1016,1044
487.58,2056,1016,1044
487.54,2064,1012,1044
487.58,2056,1016,1044
487.58,2060,1016,1044
Here is a lower cost SanDisk 8 GB class 4 card http://www.amazon.com/SanDisk-microSD-High-Capacity-microSDHC/dp/B00488G6P8 . Not bad.
SandDisk 8 GB class 4
Type is FAT32
Card size: 7.95 GB (GB = 1E9 bytes)Manufacturer ID: 0X3
OEM ID: SD
Product: SS08G
Version: 8.0
Serial number: 0XE40B0A50
Manufacturing date: 3/2014File size 5 MB
Buffer size 512 byteswrite speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
262.33,21176,1636,1945
260.62,25600,1648,1958
260.03,21880,1648,1963
260.63,17612,1612,1958
260.32,19124,1624,1961
260.21,17396,1604,1961
260.74,17220,1648,1957
260.29,17696,1616,1961
260.79,17220,1600,1957
260.28,18920,1644,1961read speed and latency
speed,max,min,avg
KB/Sec,usec,usec,usec
484.18,2088,1040,1051
484.23,2092,1040,1051
484.23,2092,1040,1051
484.18,2096,1040,1051
484.18,2096,1040,1051