disappointed in sandisk extreme 16gb class 10 45mb/s uhs-1 speed


I had very high hopes for this card…or at least some kind of measured improvement in read, write and transfer speeds. Have had the new 16gb version for several weeks and it’s actually slower than my Transcend 8gb class 6 card. Feels a bit quicker in the camera, but honestly, the transfer speeds are embarrassing.

My Sandisk 16gb extreme sdhc class 10 45mb/s card average transfer speed is rarely above 11mb/s and often as low as 7-8 mb/s…this is using my laptop’s SDHC card slot to transfer files, both to the card and from the card…other cards I have range are as good or faster…8gb Transcend class 6 avg speed = 8mb/s, 16gb Wintec class 10 avg speed = 11-12mb/s and pretec 16gb class 16 (did i say class 16? yes, it’s what the card and website say)…avg speed 11-24mb/s…it varies…not sure why…

What gives? Did Sandisk develop the UHS-1 spec to be used only in high end cameras?

Is it meant to be much slower than the competition when not used with UHS-1 capability?

It’s just crazy, seeing how Sandisk has a great rep for fast cards. They are not cheap either, and with the slow speed I feel cheated. Is there something I am missing? perhaps a firmware version that’s out there?

please help!



The issue here is that you are using a reader that does not support the new technology. To see the full speed you will need a UHS reader and you will need USB 3 ports. In USB 2 ports you will only see about 20MB/s. When technology advances you have to use hosts that can utilize it. These cards are UHS-I and will perform as advertised in UHS-I hosts anything else and you will not see the full speed. 

Sorry, not the case. My thoughts were in line with yours and I was thoroughly surprised when measuring the speed with ATTO Disk Benchmark…was expecting approx 20mb/s…actual results were

Max Values

Read: 11.8mb/s

Write: 9.4mb/s

Slower than my Transcend Class 6…so I knew something was not right. The SanDisk rep quickly approved an RMA (without my asking) and ended the discussion, after receiving the ATTO results…best guess is a knock off that was not spotted. Bought from BuyDig.com (authorized reseller). Oddly, the image on BuyDig does not match the image on their sister site, BHphoto.com. Same product ID…

Buydig image has UHS-1 logo, but not “HD Video”


BHPhoto image has “HD Video”, but no UHS-1 logo…


Oh well, once the new card arrives and tests genuine, I can get another SanDisk for my sister…she’ll love it :smiley:


mb/s should be MB/s…gb should be GB…understood I am sure…

i just got my sandisk 16gb flash drive and it totally ■■■■■!! what a ripoff this was!! the drive is so fцcking slow, its gοddamn ridiculous!! these clowns at sandisk don’t offer any fixes or solutions and just blame our computer or equipment. Fцck This!!