Types
SDSC – First generation, Secure Digital Standard Capacity.
Ver 2.0. Speed 25 MB/Sec.
SDHC – Second generation, Secure Digital High Capacity. Up to 32 GB.
Ver 2.0. Speed 25 MB/Sec.
Ver 3.0. Ultra high speed I 50 to 100 MB/Sec.
SDXC – Third generation, Secure Digital eXtended Capacity. Up to 2 TB.
Ver 2.0. Speed 25 MB/Sec.
Ver 3.0. Ultra high speed I 50 to 100 MB/Sec.
Ver 4.0. Ultra high speed II 156 to 312 MB/Sec.
| Bus interface | Card logo | Bus logo | Bus speed | Spec version |
|---|---|---|---|---|
| Default Speed |    |
— | 12.5 MByte/s | 1.01 |
| High Speed | 25 MByte/s | 2.00 | ||
| UHS-I | |
 |
12.5 MByte/s (SDR12) 25 MByte/s (SDR25) 50 MByte/s (SDR50, DDR50) 104 MByte/s (SDR104) |
3.01 |
| UHS-II |  |
156 MByte/s (FD156) 312 MByte/s (HD312) |
4.00[26] |
X Rating:
| Rating | Approx. (MB/s) |
Comparable Speed Class |
|---|---|---|
| 16× | 2.34 |  (13×) |
| 32× | 4.69 |  (27×) |
| 48× | 7.03 |  (40×) |
| 100× | 14.6 |  (67×) |
Speed Class Rating:
| Class | Minimum Serial Data Writing Speed | Application |
|---|---|---|
| Class 2 |
2 MB/s | SD video recording |
| Class 4 |
4 MB/s | High-definition video (HD) recording includingFull HD (from 720p to 1080p/1080i) |
| Class 6 |
6 MB/s | |
| Class 10 |
10 MB/s | Full HD (1080p) video recording and consecutive recording of HD stills (high-speed data bus) |
 UHS Speed Class 1 (U1) |
10 MB/s | Real-time broadcasts and large HD video files (UHS bus) |
 UHS Speed Class 3 (U3) |
30 MB/s | 4K video files (UHS bus) |
| SDSC card | SDHC card | SDHC UHS-I card | SDHC UHS-II card | SDXC card | SDXC UHS-I card | SDXC UHS-II card | SDIO card | |
|---|---|---|---|---|---|---|---|---|
| SDSC slot | Yes | No | No | No | No | No | No | No |
| SDHC slot | Yes | Yes | Yes[nb 1] | Yes[nb 1] | No | No | No | No |
| SDHC UHS-I slot | Yes | Yes | Yes | Yes[nb 2] | No | No | No | No |
| SDHC UHS-II slot | Yes | Yes | Yes | Yes | No | No | No | No |
| SDXC slot | Yes | Yes | Yes[nb 1] | Yes[nb 1] | Yes | Yes[nb 1] | Yes[nb 1] | No |
| SDXC UHS-I slot | Yes | Yes | Yes | Yes[nb 2] | Yes | Yes | Yes[nb 2] | No |
| SDXC UHS-II slot | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No |
| SDIO slot | Varies | Varies | Varies | Varies | Varies | Varies | Varies | Yes |
Based on Wikipedia:
https://en.wikipedia.org/wiki/Secure_Digital
Tools
1. Win32 Disk Imager
- A Windows tool for writing images to USB sticks or SD/CF cards
- Download here
2. Reset SDCard
3. Test tool H2Testw
- https://sosfakeflash.wordpress.com/2008/09/02/h2testw-14-gold-standard-in-detecting-usb-counterfeit-drives/
- Direct download of H2testw 1.4
4. Test tool FakeFlashTest
5. LibreELEC USB-SD Creator
- A tool to create LibreElec image.
- Download from here
6. Speed-out SDCard speed tester
More links