i recently bought a Sandisk extreme SDHC UHS-1 class 10 card (16 GB one) from flipkart. Soon after opening the package when i tested this card for its performance with Laptops inbuilt card reader, it behaved like normal class 6 card with read/write speeds of around 6MB/s (in b/w 5-6).
I tested it in several scenarios, with file format change (fat32/exFat, NTFS), with 1.26gb file transfer (from and to card), using CrystalDiskMark 3.0.2. Everywhere it didnt go beyond 6MB/s read/write speed.
Cant exactly tell that thing, but it does support SDHC/SDXC cards.
And main thing is this, that even with 4gb sony class 4 card i am getting minimum 8-10MB/s Read/Write speeds.
With 4 gb sandisk class 6 card its 12-15MB/s read/write speeds…
But with 16GB class 10 UHS-1 card it no more than 6MB/s
Issue resolved.
Problem was, i do have UHS-1 compatible reader but it was running on default windows 8 drivers.
As soon as i installed its drivers, it worked like charm with R/W speeds of ~40-46MB/s.
when on stock drivers, it wont go beyond 6MB/s.
When i tested it on an older laptop with SD/HC reader it gave R/W speeds ~ 14-20MB/s.
My conclusion:
UHS compatible reader: actual driver for reader required else it wont even run on minimum speed of 10MB/s for class 10 card. With proper drivers installed you get maxed out speeds (~ 45MB/s)
non-UHS compatible reader: even w/o required drivers, on default windows drivers it gives R/W speeds of min 10MB/s
