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I upgraded my SSD and I am now using my old one with a USB 3.0 external case. My disk speed test application shows ~150w/200r. Although when I tried to copy some games (about 30GB), speed got lower during copying. First ~10 seconds about 15-20% of files where moved, then it took another 5 mins for the rest. Is there some obvious reason why this happened, could it be some problem, or it could be because of the specific files?

System is OSX ML and I am using USB 3.0 connection.

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Not all files have the same size. If you measure your speed in files per second, this will not be accurate, especially on SSD's where copying a small file is very fast thanks to their low latency. There are tons of other factors, so generally you shouldn't fret over speed outside benchmarks as long as work is getting done, because benchmarks are not representative of real life disk usage.

could it be some problem, or it could be because of the specific files?

How would we know? We don't know what files were copied exactly. Were they game save files, or game data files? The way you worded it leaves both possibilities open to interpretation.

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Maybe its usual behaviour, I dont know either. Its game data, about 30GB total. I did transfer two times just to check that the problem wasn't from somewhere else. Also the reason I am asking is because if I could get the copying to continue with the speed it starts, it would save me lots of time. – Giannis Jan 10 '13 at 4:09
I suppose most of the small files got copied quickly, accounting for the 15-20% of files you observe, and then the rest of the files, being somewhat larger, took more time to copy. Of course, we'd all want it if we could copy very quickly all the time, but it just doesn't work that way - you don't get to choose the copy speed, all you can do is optimize your file structure for efficient copy. In particular, if you aren't going to use those game files anytime soon, you should archive them in a .tar or .zip file for storage. – Thomas Jan 10 '13 at 4:13

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