
Test Conditions and Procedures:-
1. Latest version (3.0.1) of the Crystal Disk Mark was used, which the standalone executable version in zip format can be got there;
2. Each card was freshly formatted in-camera right before carrying out each test;
3. Connected the K-5 via original dedicated USB cable, battery indication of camera was Full;
4. PC Platform: Intel E8300 Core2Duo at 2.83GHz, Windows XP Professional SP3;
5. Tested for 3 times and the best results were obtained, total data transfer size was 100MB;
Test Results:-
Card (Make/Model/Class) | Sequential Read** (MB/s) | Sequential Write* (MB/s) | Random 512k Read (MB/s) | Random 512k Write (MB/s) | Random 4k Read (MB/s) | Random 4k Write (MB/s) | Screen Capture of Test Results |
Sandisk Extreme 16GB HD Class 10/I | 11.66 | 8.940 | 11.67 | 2.841 | 2.711 | 0.828 | View |
Sandisk Ultra 16GB Class 4 | 12.13 | 5.924 | 12.08 | 1.163 | 2.883 | 1.417 | View |
Sandisk Standard 8GB Class 4 | 7.776 | 4.283 | 7.770 | 1.262 | 2.378 | 0.905 | View |
Transcend 8GB Class 6 | 12.57 | 7.075 | 12.58 | 2.133 | 3.870 | 0.029 | View |
Kingston 8GB Class 4 | 9.881 | 5.828 | 9.821 | 0.671 | 2.485 | 0.006(!) | View |
Toshiba 2GB Class 6 | 12.03 | 9.029 | 12.04 | 6.242 | 3.199 | 0.153 | View |
Toshiba 2GB Class 6 (on GF1***) | 8.237 | 6.456 | 8.271 | 4.830 | 1.344 | 0.136 | View |
Kingston 1GB Class-less (Reference Baseline) | 6.527 | 2.531 | 6.526 | 1.456 | 2.656 | 0.026 | View |
Remarks:-
* Sequential Write is the most important performance figure as most digital image and video files are usually written sequentially.
** Sequential Read affects playback time for review and determine the time for copying/moving back the image/video files from memory card to computer.
*** GF1 is also tested with the Toshiba 2GB "White Card" as it seems to perform very well in K-5 despite its age. The performance difference between the two cameras is then checked and compared. It seems that the K-5 is roughly about 50% faster than the GF1 for both reading and writing.
Update (2-23): Some people have questioned about the speed of USB of being the "limiting" factor in my test. But as I've already replied in the Comments section below, USB 2.0, which the K-5 uses, had a maximum transfer rate of 480 Mbps (Mega bits per second) in its designed specifications which is close to 60MB/s (Mega Bytes per second) roughly (assuming 1M = 1,000,000 bits and the simple fact that 1 Byte = 8 bits).
To further prove that the USB is not the bottle neck but the camera plus the card should be, the following simple test has been done for verification. I've connected an external hardisk drive with an USB 2.0 interface, via a cheap SATA-to-USB2.0 adapting case. Here is the result of the harddisk under test, which is just a typically slow 5400 rpm "250GB" one:-

All in all, the above quick test and result actually safely disproves all the unsubstantiated claims of suspecting that the USB is "not fast enough". Even if a slow harddisk with a cheap external casing can do nearly 30MB/s for both the sequential read and write! I am almost sure that if I use a better adapting case with a faster harddisk and re-do the same test again with the disk freshly formatted, the throughput rate can be even higher (and note that my that harddisk under test above is nearly full at 90% spaced used). So, the *bottle neck* must NOT the USB, but the camera+card as a whole instead!
Nevertheless, I do yet agree that the USB does incur some additional overhead in operation and thus would induce some performance loss than the real speed of the cards which could be higher, when they are read and written direclty in-camera. However, the difference should NOT be highly significant against what have been imagined and that it should be noted that it is an apple-to-apple fair comparison of this test. Furthermore, I just wish to ask what other method(s) else could do the measurement more accurately and realistically? (Not even to say to do it easily!) :-o
Simon · 684 weeks ago
RiceHigh 110p · 684 weeks ago
Josh · 684 weeks ago
RiceHigh 110p · 684 weeks ago
joergens.mi · 684 weeks ago
-Setting the K-5 to high speed (7 pictures)mode, RAW+, Manual mode, f8, 1/250, all picture improvements switched off.
-taking pixtures in Highspeed mode until picture speed reduces, now taking the time until all pictures are written, the write LED turns off, with a stop watch.
- Looking at the number of Megabytes writtem (typically 22-23picture)and dividing that by the time needed for.
The method is a little bit optimistic, because the camera starts writing immediately after the first picture is taken. But no other components are involved. And I'm not interessted in the speed of my computer or my card reader, but in the speed of the camera.
Some of the results can be seen here in a german pantax forum http://www.dslr-forum.de/showthread.php?t=1007906 especially there is a table with the results here http://www.dslr-forum.de/showpost.php?p=9384259&a...
Testing it with the K-5 and a usb cable, tests the speed of the this transfer interface not the writing speed of the card
RiceHigh 110p · 684 weeks ago
On the other hand, your mentioned method is not even theoretically correct as the write time before the camera's buffer full is NOT counted and this amount of ignored time is significant and the final throughput rate calculated will vary much depending on the write speed of the card, e.g., the faster the card is, the much higher final result than the actual throughput will be calculated.
Just imagine when there is a card that is as fast as the speed of what the camera is writing, you will obtain an infinite fast throughput rate that is unrealistic indeed. It is because the camera will not need to write back data afterwards and the waiting time is Zero in this case (for what your stop watch has been counting)! And, you can never complete this test in real as the buffer will never be overthrown (such that the camera will never slow down)!
In fact, the post #4's result of your first provided forum thread of the Sandisk UHS-I 16GB Extreme card was calculated to be 15.8MB/s, against 8.94MB/s of mine with the same card, which can be safely and quite easily explained by the time ignored for when the camera had been writing data to the card before the buffer was full, which could be about half of the actual total time required that was missed out in your calculation.
joergens.mi · 684 weeks ago
And your argument about the transfer speed is wrong. I'm using my K20D withr pk-tether an the pentax remote program in both cases the Maximum transfer speed is round about 6 MBytes, nearly the same speed that I achieve when I transfer pictures from the card to the pc by the K20.
I've written that the test is a little bit inaccurate beacuse of the prewriting time but that is simple, take the time from the first shoot to the end and my neasuremen then you will get an upper an lower border of the writing speed to card
RiceHigh 110p · 684 weeks ago
But on the other hand, ignoring the *significant* time when the camera started writing to the card before buffer overrun is the main and basic logical flaw of your suggested test as by all means a test should be designed to be accurate in principle and fundamentally correct by theory, before other practical limiting factors and assumptions are being taken into account!
joergens.mi · 684 weeks ago
- A piece of Software running on a PC
- A PC-USB-Port
- A cable connection to the Camera
- A USB-Port in the camera
- The transfer from/to the USB-Port to the card in the camera
The important things for the user is another chain
- primarly sensor to card
- and mayby for looking at a pictures the time from card to display
neither of them is tested in your test .
And as you could read, the time for taking upt to 24 photos - typically 3 seconds - can be taken into account.
Measured Value:
SanDisk Extreme Video 30 MB/sec Class 10:
17,163 MB/ sec (549.240 MB 31.96 Sekunden 44 Dateien RAW+ 22 PEF and 22 jpg)
adding 3.142 seconds the time needed for 22 pictures with 7 pictures per second
15,646 MB/sec (549.240MB 35.10 seconds )
This card has a write speed between 15.646 and 17.163 Mb/sec (the read speed in the camera wasn't testet)
RiceHigh 110p · 684 weeks ago
But your this test is actually on one extreme that large amount of data is written into the card which requires a very long time to write back the data such that the time of buffering is more or less negligible. But in normal case that if you shoot standard JPEG instead of RAW+JPEG, there is at least 4 to 5 more seconds to count in before the calculated result is to be correct.
Thanks for sharing after all! :-)
joergens.mi · 683 weeks ago
Your last sentence I don't understand. When I'm only using jpg (typical *** i didn't see any improvement on ****) why should it take 4 to 5 seconds more seconds. The process of generating the jpg is included in the RAW+ process. I did some tests with raw only, and didn't find any speed improvement (even if I koped so).
Thanks for the fruitfull discussion
RiceHigh 110p · 683 weeks ago
Ray · 683 weeks ago