Hi SanDisk Support Team,
I am writing to report a performance issue with my SanDisk Extreme 512GB microSD card. I am experiencing significantly lower speeds than advertised, and after extensive testing, I have ruled out my hardware environment.
The Issue:
My card is consistently hitting a ceiling of 90-100 MB/s for both read and write operations. Based on the product specifications and numerous benchmarks available online (using the same readers), I expect to see speeds around 160-170+ MB/s.
Testing Environment & Verification (See attached screenshots):
I have attached screenshots (including 1000003516.jpg and 1000003517.jpg) to document my testing:
Hardware: I have tested the card using both a Lexar Multi-Card 2-in-1 reader and a SanDisk MobileMate.
Connection: As shown in the attached logs, my computer identifies the connection as “SuperSpeed” (USB 3.0/5Gbps), confirming that the data path is not the bottleneck.
Card Status: The card is genuine, and the 512GB capacity is verified.
Cross-Testing: I have tested this card on three different computers, including two brand-new laptops in a shop. The result is consistently capped at ~90-100 MB/s, regardless of the machine or the reader used.
I have seen many tests on YouTube using these exact card readers where the SanDisk Extreme reaches 165-175 MB/s without issues. Since my environment is confirmed to be capable of full USB 3.0 speeds, I suspect there might be an issue with this specific card’s firmware or a compatibility bottleneck.
Could you please advise on how to resolve this, or if this indicates a defective unit that requires a replacement?
Thank you for your assistance.
