Samsung Micro SD card help - confirming read/write speed.

[Tommygunn]

I've just taken delivery of a couple of Samsung 16Gb, Class 10, UHS-1 micro SD cards and I want to confirm that they are what they say they are.
I've run a test using 'H2testw' on one of the cards and I got the following:
Read: 20.5 MByte/s
Write: 14.7 Mbyte/s

I also ran a comparison test on my old Sandisk 8Gb, class 6 SD card (I think it's an Ultra but the labels is missing, I do have it somewhere) and got the following:
Read: 20.2 MByte/s
Write: 16.6 MByte/s

I'm no expert on all the conversions and the bits/bytes but I would have expected the Samsung card to be well above the results of the old Sandisk, but they're not.

Also, how do the results of the Samsung card match up to the stated 'Up to' amounts of 70MB/s and 20MB/s?
I've tried various conversion tables and the results seem so far apart I'm not sure I'm reading them correctly.

Cheers,
Tom.

 

[Folterknecht]

Did you use a card reader in your PC? Is that thing even USB 3.0 compatible and connected to an USB 3 port?

 

[Tommygunn]

I used the built in slot on my laptop.

Tom.

 

[95Viper]

What is the port connected to on your laptop? Or, what is the make and model of the laptop?

 

[Tommygunn]

It´s an HP 6550b.

Tom.

 

[Folterknecht]

As far as I can see your notebook is the limiting factor here with only USB 2.0 speeds (~30 MB/s) max. If you want to see if the cards perform as advertised (or near it) you 'll have to use a card reader, that is connected via USB 3.0 and capable of USB 3.0.

 

[hojnikb]

You probably have a slower, SD25 compatible card read, which explains those speeds.
To fully utilize the card, you need an uhs-i ready card reader.

 

[95Viper]

My guess... is you are hitting the limit on the card reader. It looks like HP is replacing the Expresscard/54 slot and connects to USB 2.0; as, all I see are USB 2.0 on that laptop.

On a UHS-1 card, I get about 35Mbs and on a class 10 card, it stays around 25Mbs. My card reader is on a USB 3.0 port.

Here are some good reads:

Difference between Speed Class, UHS Speed Class, and Speed Ratings (performance) for SD/SDHC/SDXC cards

And, here is a quote from SanDisk products transfer speed about the speeds...

Host devices
The transfer speed of a storage product can greatly be affected by the host device. If a host device such as a camera can only achieve for example a 20MB/s write speed, placing a card with a 90MB/s write speed in the camera will NOT improve the performance of the camera. The card WILL be limited to the write speed provided by the host. When shopping for a storage device, it is best to look at the performance specifications of the host and choose an equivalent storage device.

Host limitations are commonly seen with low end card readers such as internal or built in card readers on laptop and desktop computers. To achieve the best performance, a high speed external USB 2.0, USB 3.0 or ExpressCard reader is recommended.

 

[Tommygunn]

I just ran a test with the two makes transfering photo and video data of 1.03Gb, back and forth. I did three tests:
1) Copied file and transfered it to the cards.
2) Copied transfered file back to laptop.
3) Pasted the file back to the laptop.

I got the following times:

Samsung 1)1m 54secs, 2) 56secs, 3) 58secs
Sandisk 1) 2m 28secs, 2) 55secs, 3) 1m

In the main the Samsung is better than the Sandisk but can anyone explain the similarity in times for tests 2 & 3?

Tom.