On 3/2/21 7:20 PM, Roger Heflin wrote:
One complication. You said you aren't using a HUB, that is probably not exactly true. Almost all of the USB ports on a laptop or a desktop are using a HUB, very few of the ports are dedicated. Typically a laptop or desktop has at most 3 actual real underlying ports, and some do not even have that many.
ok sorry for the unclear description: I am not using any external HUB. The latop has 2 USB ports (3rd gen) and 3 for the 6th gen.
Because of this there could be some other devices on the HUB effecting it.
Also, the copy speed once you get above 50MB/sec can be affected by the device you are copying from. Also also on the device you are copying if the file sizes are different then you cannot compare MB/sec since on small files (say 64k) the overhead for each new file is significant.
In every instance I was making a backup of the same files (not the same on both machines - but then again you can see the performance do not seem to be machine related) stored on the internal SSD disk. Roughly 3-400GB I'd say for both machines.
Make sure to test single big files if you want to determine speed, and do not call the test finished until a sync returns as with smaller tests there could be a significant amount of data in the host os cache causing the rate to look much better than it actually is. Checking grep -i Dirty /proc/meminfo will tell you how much is in said cache at the end of the test.
What is puzzling (to me) is the performance disparity between the 2 machines AND the version of Fedora, especially since I cannot even conclude Fxx is faster/better than Fyy.
Thank you.
Fred