Review on 128GB SanDisk Ultra Dual Drive USB Type-C - USB-C, USB 3.1 (SDDDC2-128G-G46) Gray by Clayton Jimenez

I usually love SanDisk products - I record everything on Sandisk SD cards. However, this flash drive is incredibly one-sided. If there are already files on it, it reads them at high speed (150 MB/s). If you're copying files to a 3.1-enabled device, it's fine in that regard. However, flash drives are not just for storing read-only files. Half the point is to write files on it so they can be moved somewhere else, and in that regard this product falls short. When I first received this drive, I did a test and backed up about 6GB of AVCHD 1080p video to several places: this drive, a 1TB USB 3.0 external hard drive, and a cheap ADATA 32GB USB 3.0 flash -Drive. The files were copied from an NVMe M.2 SSD so there was no bottleneck and I connected the USB-A side to a USB 3.1 compatible port on my motherboard (and later repeated with the USB-C side) . on a laptop, also with an M.2 SSD inside, with the same performance). Write speeds on this drive spiked to 90 Mbps for a few seconds, then dropped to a painfully slow 20 Mbps average. In the same test, an ADATA USB 3.0 flash drive recorded at a steady 50 Mbit/s and a USB 3.0 external hard drive recorded at 90 Mbit/s. It doesn't matter much for small files, but for anything over 500MB, be prepared to increase your timeout significantly. Writing to this drive at half the speed of a cheap USB 3.0 flash drive is insane. The only time you'll get USB 3.1 speeds is when reading, which makes it excellent, but most importantly, to be able to read any of it you'll have to write to it at incredibly slow speeds first. This makes it a very niche drive, only good for short bursts of files where you don't need USB 3.1 speeds to begin with. If it were a small capacity drive it would make sense, but considering it can go up to 128GB it will appeal to people like me who want to copy large files at USB 3.1 speeds, and will end up being a big disappointment if 5+ is required. Minutes to copy a few gigabytes of video. The only scenario where this makes sense is copying files from a smartphone, but at this point the phone comes with a USB-C charging cable that works just as well, if not faster, for copying files. Cannot recommend this for any reasonable scenario.