MicroSDHC Mobile Ultra 16GB red and gray performance

Hi there, I just got a new MicroSDHC Mobile Ultra 16GB card (red and grey version) and I was expecting it to perform really well. I already had two other Sandisk MicroSDHC 16GB Class 2 cards and I ran some write and read tests using a Mobile Mate card reader. I was quite surprised to find out that the first 16GB I got is by far the fastest and the new card is barely faster than the second Class 2 card I bought.

I did the tests several times and with a couple computers, copying to the card (write speed) and then copying from the card to my HD (read speed) a single large .avi file of 673MB, measuring the time needed for the transfer.

Here are the results:

MicroSDHC 16GB Class 2, serial number 0826302875DC1, bought the 7th of December of 2008.

Write speed: 12,8MB/s  Read speed: 18,4MB/s

MicroSDHC 16GB Class 2, serial number 1008203512D8D, bought the 18th of December of 2010.

Write speed: 7,1MB/s  Read speed: 18,6MB/s

MicroSDHC Mobile Ultra 16GB , serial number 114108651D, bought the 30th of November of 2011.

Write speed: 7,6MB/s  Read speed: 18,5MB/s

The reader: Mobile Mate Micro, serial AE0806XXJ

All the figures above match and even exceed the class rating of each card. The Mobile Ultra card is advertised to reach up to 30MB/s read speeds, but that might just be caused by the reader reaching its maximum speed.

With all said I can’t really complain, but I’m a bit disappointed and upset about the fact that the newer card is so much slower at writing than the first one I got 3 years ago; I was expecting technollogy to get faster instead of slower, specially when that’s one of the main advertising points.

The same happened to me when the 8GB Sandisk MicroSDHC cards came out. I bought one shortly after their release that performed great and a couple years later I bought another one with same specifications that could only write at half the speed.

Any ideas on what could be the reason for this or am I just missing something?

Thanks for reading!

Beside the microSDHC logo on the card you should see a roman numeral I. This means the card is a UHS card. UHS card will require a reader that support UHS. to see the full speeds you will need a few things. USB 3.0 ports and a UHS compatible reader such as the one linked below.


also take a look at the asterisk text in the product discription

 Up to 30 MB/sec read speed. Write speed lower. Based on SanDisk internal testing; performance may be lower depending on host device. 1 megabyte (MB) = 1 million bytes.

Thanks a lot for the reply drlucky. Indeed, this new card is supposed to be UHS I, so it’s very likely that it can reach faster read speeds than what I have mesured so far with a faster, UHS compatible, reader.

My current reader never displayed speeds above 20MB/s with any of my cards, and it always tops up at around that speed, so it is for sure what is limiting the read speeds of all the cards.

On the other hand, with the write speeds, do you think this card could also reach faster write speeds when used with an UHS compatible reader? I was assuming that if the card was not reaching the maximum write speed limit of my current card reader, it would not go faster with a faster reader either. I’m getting 67% faster write speeds with my first 16GB card with my current reader.

If anyone has had the chance of testing these new UHS I MicroSDHC cards with an UHS compatible reader, it would be great if they could post their results here to check this point.


I actually have this card, and using it with the kingston USB 3.0 and UHS 1 specification reader.

I get the following read speed

non uhs 1 reader 11mb/s

uhs1 reader 38b/s

I cannot remember the write speed, but will update this post later on…

Thanks for the feedback kms, that is a major increase in read speed while using a UHS-I reader. From what I learned, UHS-I mode works at higher clock rates, so it should increase both read and write speeds, so it would be interesting to see what write speeds can this card achieve in UHS-I mode.

To compare results I would recommend using CrystalDiskMark software, a free and widely spread drive performance benchmark.

For reference here are the results I got from my MicroSDHC Mobile Ultra 16GB UHS-I when used with a USB 2.0 reader (so no UHS-I capable):

CrystalDiskMark 3.0.1 © 2007-2010 hiyohiyo
                           Crystal Dew World : http://crystalmark.info/

* MB/s = 1,000,000 byte/s [SATA/300 = 300,000,000 byte/s]

           Sequential Read :    19.709 MB/s
          Sequential Write :     8.221 MB/s
         Random Read 512KB :    19.314 MB/s
        Random Write 512KB :     0.799 MB/s
    Random Read 4KB (QD=1) :     3.631 MB/s [   886.6 IOPS]
   Random Write 4KB (QD=1) :     2.189 MB/s [   534.5 IOPS]
   Random Read 4KB (QD=32) :     3.403 MB/s [   830.9 IOPS]
  Random Write 4KB (QD=32) :     0.497 MB/s [   121.4 IOPS]

  Test : 500 MB [M: 30.4% (4.5/14.8 GB)] (x2)
  Date : 2012/01/22 21:18:58
    OS : Windows XP Professional SP3 [5.1 Build 2600] (x86)
    Sandisk MicroSDHC 16GB UHS-I