Posted by CANbike on Mon, 27 May 2013

Benchmark: SanDisk Ultra SDHC UHS-I Class 6 (4GB)

Sandisk Ultra SDHC UHS-I 4GB-01-thumb.jpgSandisk Ultra SDHC UHS-I 4GB-02-thumb.jpgSandisk Ultra SDHC UHS-I 4GB-03-thumb.jpg

The SanDisk Ultra SDHC UHS-I Class 6 (4GB) cards can often be found for around $8. However, the Class 6, 4GB model is no longer listed on their website and has been replaced by newer models.

This particular SD card was rated as Class 6, and advertised as having quick transfers up to 30 MB/s. Of course there was a disclaimer that write speeds are lower than read speeds, etc.

A standard card reader on a desktop computer was used for the benchmark. It handles SDHC cards and is not UHS-I rated. As result, the full potential of this card may not be realized. However, a transfer rate of 30 MB/s is within it’s range as it uses a USB 2.0 bus to communicate with the built-in card reader.

The read speed came in around 18 MB/s and the write speeds were around 12 MB/s.

The 30 MB/s quick transfer was not achieved. However, a UHS-I rated device was not used and could be the difference.

On the other hand, the sustained write speed of around 12 MB/s was well above the certified Class 6 rating. A Class 6 SD card must be able to sustain a write speed of 6 MB/s. But based on the benchmark, this could easily be a Class 10 rated SDHC card.

Overall, the SanDisk Ultra SDHC UHS-I Class 6 (4GB) cards are a great value. The performance is on the high end for it’s price and Class 6 category. Just be wary of the claimed quick transfers up to 30 MB/s, which was full of disclaimers on the packaging.

Benchmarked below is the SanDisk Ultra SDHC UHS-I Class 6 (4GB) card formated to have a single fat32 partition.

Device Information

fdisk -l  /dev/sdd

Disk /dev/sdd: 3965 MB, 3965190144 bytes
3 heads, 32 sectors/track, 80672 cylinders, total 7744512 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000d59f7

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1            2048     7743487     3870720    b  W95 FAT32

Device Read Benchmark

hdparm -t  /dev/sdd1

/dev/sdd1:
 Timing buffered disk reads:  54 MB in  3.00 seconds =  18.00 MB/sec

Device Write Benchmark: 1MB x 1000

dd if=/dev/zero of=tempfile bs=1M count=1000 conv=fdatasync,notrunc
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 86.0865 s, 12.2 MB/s

Device Write Benchmark: 10MB x 100

dd if=/dev/zero of=tempfile bs=10M count=100 conv=fdatasync,notrunc
100+0 records in
100+0 records out
1048576000 bytes (1.0 GB) copied, 84.9458 s, 12.3 MB/s

Device Write Benchmark: 100MB x 10

dd if=/dev/zero of=tempfile bs=100M count=10 conv=fdatasync,notrunc
10+0 records in
10+0 records out
1048576000 bytes (1.0 GB) copied, 85.8805 s, 12.2 MB/s

Device Write Benchmark: 500MB x 2

dd if=/dev/zero of=tempfile bs=500M count=2 conv=fdatasync,notrunc
2+0 records in
2+0 records out
1048576000 bytes (1.0 GB) copied, 87.5836 s, 12.0 MB/s

Device Write Benchmark: 1000MB x 1

dd if=/dev/zero of=tempfile bs=1000M count=1 conv=fdatasync,notrunc
1+0 records in
1+0 records out
1048576000 bytes (1.0 GB) copied, 90.8444 s, 11.5 MB/s