[davidreilly3207]

At the suggestion of user UnknownVT in this thread, I setup testing of my SDHC cards using the freeware CrystalDiskMark 3.0.2 x64 disk utility. The results are in the jpeg below.

The average write speed results seemed to validate the original in camera results. The surprise was in the variation among different cards of the same type. One Transcend Class 10 16gb was markedly better than the other while two of the Transcend Class 6 16gb cards were far below the other two and only on par with the Kingston Class 4 8gb cards. The Muskin Class 10 32gb cards were barely up to the performance of the worst of the Transcend Class 6 16gb cards and the Kingston Class 4 8gb cards.

I have a pair of SanDisk Ultra 16GB SDHC UHS-I Class 10 Memory Cards [SDSDU016GA11] on the way and hope they will improve the write times on my K20D.

Thanks to UnknownVT for his suggestion

Attached Images

 

[Chaos_Realm]

At the suggestion of user UnknownVT in this thread, I setup testing of my SDHC cards using the freeware CrystalDiskMark 3.0.2 x64 disk utility. The results are in the jpeg below.

The average write speed results seemed to validate the original in camera results. The surprise was in the variation among different cards of the same type. One Transcend Class 10 16gb was markedly better than the other while two of the Transcend Class 6 16gb cards were far below the other two and only on par with the Kingston Class 4 8gb cards. The Muskin Class 10 32gb cards were barely up to the performance of the worst of the Transcend Class 6 16gb cards and the Kingston Class 4 8gb cards.

I have a pair of SanDisk Ultra 16GB SDHC UHS-I Class 10 Memory Cards [SDSDU016GA11] on the way and hope they will improve the write times on my K20D.

Thanks to UnknownVT for his suggestion

Not sure about this mate,

What type of interface does your card reader use?

I am going to guess you have USB 2? As you seem to have a bottle neck, since class 10 cards- 18mb/s read and class 4 cards = 18mb/s read speed.

USB 3.0 will give you a noticeable improvement, especially in the read speed for uploading to your computer.

I did a bit of testing a while ago over HERE and got some good results.

[dosdan]

The surprise was in the variation among different cards of the same type. One Transcend Class 10 16gb was markedly better than the other while two of the Transcend Class 6 16gb cards were far below the other two and only on par with the Kingston Class 4 8gb cards. The Muskin Class 10 32gb cards were barely up to the performance of the worst of the Transcend Class 6 16gb cards and the Kingston Class 4 8gb cards.

All the manufacturer has to do is meet the class speed spec, which all these cards do. For example, "Class 6" simply means that the min. write speed is at least 6Mbps. The spec says nothing about read speed performance.

It's not hard for modern SD cards to reach 10Mbps write speed.

Dan.

[Kona]

I have Sandisk ExtremePro (U1) and would like to see such compared to these cards. I know Pentax won't write > 30Mb/s but it's nice to have faster reads for dumping a few gig to PC.

[davidreilly3207]

I should have stated that all the cards meet the minimum standard of read/write @ 10 MB/s, but in the original thread I was more interested in the actual write speeds in camera.
I have a USB 3.0 card reader on the way and have available usb 3.0 ports on my computer and that should improve read speeds.
I have marked and plan on using the Transcend Class 10 16 Gb that tested the best when write speed is important, as when taking auto bracketed multiple shots of sports, unless the new Sandisks on the way write faster.

[rawr]

have a USB 3.0 card reader on the way and have available usb 3.0 ports on my computer and that should improve read speeds.

Cool.

I have a suggestion - run a test series by just using the camera as the card reader. Should be possible since it can function as a USB device. It will give a more realistic dimension, perhaps, to the test results.

Plus I always got the impression, when copying files to my computer off the camera via a USB cable alone, that the camera makes a pretty fast card reader.

[Chaos_Realm]

Plus I always got the impression, when copying files to my computer off the camera via a USB cable alone, that the camera makes a pretty fast card reader.

When I did the tests in the link I posted above, the camera was about 1/3-1/4 of the speed of the usb3 card reader. In other words I found it to be significantly slower

[davidreilly3207]

As I said, the original purpose of the testing was to find the best write speed. Testing using the camera as the device would only test read speeds. As Chaos_Realm stated, the camera is significantly slower than a usb 3.0 reader and I have found it to be significantly slower than a usb 2.0 reader.

[UnknownVT]

As I said, the original purpose of the testing was to find the best write speed. Testing using the camera as the device would only test read speeds. As Chaos_Realm stated, the camera is significantly slower than a usb 3.0 reader and I have found it to be significantly slower than a usb 2.0 reader.

Thanks for reporting the CrystalDiskMark speeds -
Hopefully the USB3.0 reader will show whether it's the USB2.0 throttling the read speed (either reader or port)

The Transcend seem to be good performers at reasonable prices one of my fastest cards is a Transcend 8GB class 10 -

This is with a cheapo (99cent) USB2.0 reader

Camera USB connections are usually much slower than good card readers -

from dpReview of the Pentax K20D


and Imaging-Resource.com on Pentax K20D


PS - the surprise to me was how well the Kingston class 4 performed - it's in class 10 territory

[rawr]

OK, scratch the idea of using the camera as a reader The camera body as a reader sounds way too slow, and the fastest way to copy data from an SD card onto a PC is clearly via an external reader, pref a USB 3 one. Noted!

But on the other side of the coin, what is the data throughput ceiling of the camera as a SD card writer? It seems that a lot of the write performance of many SD cards may be wasted if the camera body (with the latest applicable firmware etc) has a fixed limit on its data write speed.

This topic may have been covered 1000 times before, so forgive me for asking here, but is there any test data or specs on the maximum speed a camera like the K-x or K-5 can actually write data to a SD card?

[JimJohnson]

A computer with a built-in SD card reader should in theory be even faster than any USB based card reader.

[southlander]

A computer with a built-in SD card reader should in theory be even faster than any USB based card reader.

Not sure why. Inside the PC a built in card reader is merely plugged into a USB header connection on the m/board. It doesn't use hard drive buses or anything like that.

[UnknownVT]

Not sure why. Inside the PC a built in card reader is merely plugged into a USB header connection on the m/board. It doesn't use hard drive buses or anything like that.

This sounds about right.
If the motherboard is only spec'd to USB2.0 say, then a built-in card reader I believe can only be to USB2.0.
The only variable that may be eliminated would be any separate/external USB card reader.

Just to make things less clear -
here are some results that I've literally just taken as I write -
Same Transcend 8GB class 10 SDHC card as above:

PC card slot:


USB2.0 port using same cheapo (99cent) USB2.0 SDHC reader:


One may have thought the PC's own card reader slot ought to be faster since there are less intervening interfaces -
but strangely enough the PC's USB2.0 port and using just a cheapo USB2.0 reader actually gave faster results -
note: these are averages of 3 consecutive readings and I did this twice to confirm the results did not vary to any significant degree.

I think this may show that the USB card reader is not limiting the read speed?

I only have USB2.0 ports - but to prove that the ports are not limiting the SDHC card results -
I do have an USB3.0 flash drive (aData model # AS102P-16G-RGY) spec'd at:
Read Speed up to 100 MB/s; Write Speed up to 25 MB/s
- and these were the readings:

These are obviously limited by the USB2.0 spec's of my PC -
but they do show the USB2.0 port is capable of at least higher read speeds >30MB/s and write speeds >22MB/s for those SDHC card readings.

[tromboads]

But surely we are only interested in the write and read speed from the camera? Stuff the USB drives native or not.

Also, built in card readers are still USB devices, ie they are still sent through the same controler any external USB device would go through.

[DeadJohn]

Regarding internal and external readers giving different speeds on the same computer, some motherboards have multiple banks of USB (and SATA) ports. One bank might be controlled by the primary chipset while another bank has a different model of controller. One controller can be designed more "efficiently" than the other and allow faster transfers.