If your 32GB SSD had 4x 8GB chips, it would still be 4x faster than the USB stick at any write operation. I have a super talent 32GB USB SSD in the neighboring port and it works at expected speeds.Ī garden variety USB stick usually consists of flash memory chips that are written to serially (sequentially), and does not have any cache of its own.Īn SSD, on the other hand, contains a controller which writes to the flash memory chips parallel, increasing the throughput by a factor of 2 or more over the USB stick. Write speeds of a USB stick and an SSD cannot be compared This affects hard drives too, but to a somewhat lesser extent. Writing lots of small files, or even mixed data containing a number of small files can slow the process down a lot. Writing lots of files, especially small ones, is slowīecause of the way flash memory and filesystems work, the fastest throughput (speed) is achieved when writing very large files. Such copying in Windows may seem faster (including the reported MB/sec speeds) because sometimes Windows will not wait for the sync, and declare the job completed as soon as the data is written to cache. If you abort at that point, the data is corrupted (as you noted) since the sync never finished. Caching copy operations to slow devices results in the behavior you see - the "fast completion" is actually writing to the cache, and then it slows and stops because the actual flushing of the data in the cache (sync) to the slow device is taking very long. Linux (and Windows) will use otherwise "empty" RAM to cache read/write operations and make them faster on subsequent accesses. One thing you need to understand is file caching. The problem I seem to see in the GUI is that the progress bar goes to 90% almost instantly, completes to 100% a little slower and then hangs there for 10 minutes. File caching can make writes appear slower or faster Why is copying to my USB drive so slow in Linux (and faster in Windows)? sd 8:0:0:0: Attached SCSI removable disk sd 8:0:0:0: Assuming drive cache: write through sd 8:0:0:0: No Caching mode page present sd 8:0:0:0: Attached scsi generic sg4 type 0 scsi 8:0:0:0: Direct-Access SanDisk Cruzer 1.14 PQ: 0 ANSI: 2 If I wait for it to complete the copy is successful.Īny ideas? dmesg output below: usb 2-1.2: new high-speed USB device number 5 using ehci_hcd Interrupting the copy at this point seems to result in corruption at the tail end of the file. I have a super talent 32GB USB SSD in the neighboring port and it works at expected speeds. To copy 1.8GB takes me over 10 minutes (it should be < 3 min.) I have two identical SanDisk Cruzer 8GB sticks, and I have the same problem with both. When I copy files to the USB device, it takes much longer than in windows (same usb device, same port) it's faster than USB 1.0 speeds (1MB/s) but much slower than USB 2.0 speeds (12MB/s).
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