Top critical review
5 people found this helpful
Much slower than advertised, also compatibility issues.
on 12 November 2010
133x should be achieve a maximum transfer rate of about 21 MB/s. This card can't. In fact you can't even *read* data at anything like that speed, let alone write it.
Real world measurements:
Read test, performed 3 times: # for i in 1 2 3; do hdparm -tT /dev/sdc1; done
The second figure in each case is the significant one. The first figure only refers to the buffer while the second is the real world read performance.
Timing cached reads: 1680 MB in 2.00 seconds = 840.23 MB/sec
Timing buffered disk reads: 54 MB in 3.03 seconds = 17.82 MB/sec
Timing cached reads: 1632 MB in 2.00 seconds = 815.62 MB/sec
Timing buffered disk reads: 54 MB in 3.03 seconds = 17.83 MB/sec
Timing cached reads: 1706 MB in 2.00 seconds = 852.97 MB/sec
Timing buffered disk reads: 54 MB in 3.03 seconds = 17.84 MB/sec
So less than 18 MB/s...a little disappointing.
I then performed a write test twice and each run was identical. The test is simple; write a 4GB file and print the time taken and rate of transfer:
# dd if=/dev/zero of=/media/disk/output.img bs=8k count=512k
4294967295 bytes (4.3 GB) copied, 330.627 s, 13.0 MB/s
13 MB/s is just about OK but not more than that, while the read speed of about 18 MB/s is also much poorer than I expected.
I think the card is OK. In compatible equipment it seems fine. But that word 'compatible' is crucial, and also the card cannot perform anywhere near the claimed speeds. In my DSLR, an old Konica Minolta Dynax 7D, it works fine and easily outperforms unbranded generic cards and an old Kingston Elite Pro. In my compact, a Canon Powershot S70, it's not useable as it causes the camera to brainfart and results in corrupted files and I'm forced to power off and start again. In theory there is no limit on the size of CF card the camera can use and of course I format the card in the camera. I've also found that my PC's built in card reader doesn't always recognise the card (it's a modern enough reader, for example it reliably handles micro SDHC at full speed). So while the card works well enough in my DSLR it's quite annoying that it doesn't work well with another camera and a card reader. I wouldn't buy the same card or brand again, even though it's cheap.