Bests & Worsts Reviews from Amazon

The SanDisk Extreme 64GB is a solid drive overall, just be mindful of what you want to use it for and what you expect for performance. For large, sequential transfers, Sandisk's performance estimates are almost exactly on the mark. CrystalDiskMark measures the sequential transfer rate at 250MB/sec read and 180MB/sec write, which is fast enough that you'll just about need a solid state drive of some kind in order to feed it data as fast as it can write it out. If you just want to dump a bunch of files and go in the minimum amount of time necessary, then this is the perfect drive. However random read/write performance is not nearly as strong. Even 512K random writes are down to 53MB/sec, and 4K random reads and writes drop to 10MB/sec. Though this will beat most hard drives and a number of other USB flash drives, for anyone expecting to treat this as a regular SSD in USB form factor, random performance is but a fraction of the performance of a modern SSD. Writes in particular are an order of magnitude lower than modern SSDs, so as a portable SSD running an OS (e.g. Windows-To-Go) it's not going to deliver that same fast random performance. Under the hood this drive is based on SanDisk's older U100 SSD controller, which explains the results above. U100 is known for its strong sequential performance but weak random performance, exactly the same as this flash drive. This coupled with the limited amount of NAND and lack of write caching (since it needs to be removable) leads to the overall limited random performance. Also of note, this drive presents itself as a SATA-over-USB drive under Windows rather than a pure USB drive, which means it can be SMART monitored and TRIM is supported. Finally, for what it is worth my 64GB drive identifies itself as a removable drive rather than a fixed drive as some other reviews have noted. It's not clear whether SanDisk has made a production change or this is somehow an older drive, but it does mean the specific drive I received is fully bootable. Overall this is an excellent drive for storing or copying files at high speeds, which is exactly what I needed it for. Just don't expect SSD-like random read/write performance from the drive; for that there are better (albeit more expensive) options.