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rMBP 15" - Two USB 3.0 ports, 2 different transfer speeds
- Thread starter foto-max
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How do you measure the transfer rate and can you tell us what kind of unit "GPS" is? Transfer rates are either measured in Bits per second (bps or b/s) or Bytes per second (Bps or B/s), thus you should report it in either xy Megabit/s (Mbps or Mb/s) or xy MegaByte per second (MBps or MB/s).
get blackmagic disk speed test from the app store.
it will give you the most consistant numbers, and provides a good benchmark when comparing multiple situations.
it will give you the most consistant numbers, and provides a good benchmark when comparing multiple situations.
If they were Mbps then it would be under 6.25 MB/s or over 25 MB/s. But I guess you experienced 50 MB/s and 200 MB/s.
You could also try these:
One port reports 50 MB/s and less, and port reports 200 MB/s and more?
Maybe it has something to do with power?
My (old) understanding is that Unix uses otherwise free memory as file buffers. The first time you run a test a given file is read/written from/to actual disk. The seconds time it may be in central memory. As mention by waw74, black magic speed tester propably would not be affected by this.
