I just tested mine. Here are the results....
Warning: Only 3813 of 3815 MByte tested.
Test finished without errors.
You can now delete the test files *.h2w or verify them again.
Writing speed: 10.1 MByte/s
Reading speed: 21.9 MByte/s
H2testw v1.4
Files on the card will cause that warning.
Is that the card for the Navi or a camera card?