When you select some files and copy them, the file copying dialog appears with progress bar and speed indicators. But when you select some other files and copy them, another dialog pops up and both seemingly show more than 50% speed slowdown as compared to only a single file copying dialog. I'm fairly sure that back in the days doing this with a floppy disk actually did slow down the process significantly. But is it the case with HDDs and SSDs in modern Windows OSs?
Does copying several batches of files through multiple file copying dialogues slow down overall I/O operation in Windows 7?
For example, let's copy a hundred of 50 MB files from HDD A to HDD B and right after that copy another hundred of other 50 MB files from A to B. So the files aren't small and the slowdown isn't caused by file table stuff issues due to small size. Both disks are 90% empty and contain no fragmented files, so there are no problems coming from that way too. Disks are connected via SATA, and aren't external.