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--- memorycards [2019.11.19 20:17] – created Steve Isenberg
+++ memorycards [2024.11.12 15:56] (current) – Steve Isenberg
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 =====Memory Cards Info=====
 [[https://www.bhphotovideo.com/explora/computers/buying-guide/the-fastest-memory-cards-money-can-buy|info about different SD and Micro SD cards and their ratings]] Class 10 vs 6 vs 4; UHS-I and UHS-II; V60 and V90; and more.
+Many cheap too-good-to-be-true SD cards are indeed not the rated size.  See [[https://www.makeuseof.com/tag/how-to-spot-fake-microsd-card/|this article]] in MakeUseOf to spot fake ones.  It discusses software you can use to see if the SD or TF card is not the size it claims to be: FakeFlashTest, H2testw, ChipGenius.  What to do if you're stuck with a fake card (maybe you can determine its real size and use it or maybe you can fix it using DiskPart).  All software is Windows.
+From [[https://www.makeuseof.com/tag/5-mistakes-avoid-buying-next-microsd-card/]]
+There are four SD card formats:
+  - **microSD**: Has a capacity up to 2GB, and works in any microSD slot.
+  - **microSDHC**: Has a capacity of more than 2GB and up to 32GB, and works in hardware that supports either SDHC and SDXC.
+  - **microSDXC**: Has a capacity of more than 32GB and up to 2TB (although at the time of writing, 1TB is the largest available card), and is only supported in SDXC-compatible devices.
+  - **microSDUC**: Supports cards up to 128TB, and will require a compatible device.
+{{:choosingsdcards.png?400 |}}
+Speed Class
+  *     **Class 2**: At least 2MBps.
+  *     **Class 4**: At least 4MBps.
+  *    **Class 6**: At least 6MBps.
+  *     **Class 10**: At least 10MBps.
+UHS Speed Class
+  *     **U1**: A write speed of at least 10MBps.
+  *     **U3**: A write speed of at least 30MBps.
+Application Performance Class
+  *     **A1**: Minimum random read speed of 1500IOPS; random write speed of 500IOPS.
+  *     **A2**: Minimum random read speed of 4000IOPS; random write speed of 200IOPS.
+Video Speed Class
+  *     **V6**: Minimum write speed of 6MBps.
+  *     **V10**: Minimum write speed of 10MBps.
+  *     **V30**: Minimum write speed of 30MBps.
+  *     **V60**: Minimum write speed of 60MBps.
+  *    ** V90**: Minimum write speed of 90MBps.
+This diagram comes from MakeUseOf at the URL above.\\
+The SD Card Association recommends U3 or better for 4K video. If your card's write speed is too slow, it will drop frames and produce stuttering video.
+|Workload|Min Write Speed|Rating|
+|8K video @ 60/120 FPS| 60MB/s|V90 or V60|
+|1080p/4K video @ 60/120 FPS|30MB/s|V30, U3|
+|720p/1808p/4K video|10MB/s|Class 10, V10, U1|
+|720p/1080p video, 4K video possible|6MB/s|V6, Class 6|
+This info from [[https://www.makeuseof.com/tag/best-fastest-microsd-cards/]]
+==== Measuring Transfer Speeds Between Your MacBook and Thumb Drives ====
+//This information provided by ChatGPT 11/12/2024//
+To measure transfer speeds between your MacBook and various thumb drives, you can use benchmarking tools that provide detailed read and write speeds. Here are some effective methods and tools:
+=== 1. Blackmagic Disk Speed Test ===
+  * **About**: Blackmagic Disk Speed Test is a popular, free utility for macOS users to measure the performance of external storage devices.
+  * **How to Use**:
+    - Download it from the Mac App Store.
+    - Open the application and select your thumb drive as the target disk.
+    - Click “Start” to begin the test, which will show both read and write speeds.
+  * **Advantages**: Simple and quick to use, with a clear display of read and write speeds. Good for comparison across different drives.
+  * **20241112: this is not working for thumb drives on my MacBook Pro. I selected a thumb drive and clicked Start; nothing happened.**
+=== 2. AJA System Test Lite ===
+  * **About**: AJA System Test Lite is a popular benchmarking tool designed to measure the performance of storage devices, widely used by video professionals.
+  * **How to Use**:
+    - Download AJA System Test Lite from AJA’s website (it’s free).
+    - Select your thumb drive as the target and specify the test file size (1GB is a common choice).
+    - Start the test, which will show sequential read and write speeds.
+  * **Advantages**: Offers more configuration options than Blackmagic, allowing you to test different file sizes and formats.
+=== 3. Terminal Commands (Using dd) ===
+  * **About**: If you prefer a command-line approach, you can use the `dd` command in Terminal to measure read and write speeds.
+  * **How to Use**:
+    - **Write Speed**: Open Terminal and enter:\\ ''time dd if=/dev/zero of=/Volumes/YourDriveName/testfile bs=1024k count=1024''\\ //Replace //''YourDriveName''// with the name of your thumb drive.//
+    - **Read Speed**: After creating the test file, enter:\\ ''time dd if=/Volumes/YourDriveName/testfile of=/dev/null bs=1024k''
+    - **Interpretation**: The time reported at the end shows how long the data transfer took, from which you can calculate the speed.
+  * **Advantages**: Flexible and works without any additional software.
+=== 4. Disk Utility (Indirect) ===
+  * **About**: While Disk Utility on macOS doesn’t directly measure speed, it can help identify if the drive is connected at the correct speed.
+  * **How to Use**:
+    - Open **Disk Utility** and select your thumb drive.
+    - Go to **Info** to see if it’s connected at USB 3.2 speeds or lower.
+  * **Advantages**: Useful for troubleshooting connectivity issues or confirming connection speed, though it won’t directly show transfer rates.
+Using any of these methods will give you a good idea of your thumb drives’ actual read and write speeds. Blackmagic Disk Speed Test is usually the easiest for quick results, while the `dd` method in Terminal is a great way to measure without any added software.