Hash sum checkup for several files at the same time (files are already exist)

[nockdown]

I add torrent that is already downloaded (that I have on my hard drive) for hashing and seeding. Then I add next one for the same while the first one is still hashing. Second one stands in a queue.
So the first question: Why can not qBittorrent check hash sum for several files at the same time?

After hashing of first file is finished, checkup hash sum for second file starts in probability 50%. Sometimes qBittorrent begins downloading instead of hashing in spite of such file is already exists on hard drive in needed place with needed name. It's my second question.

Sorry for my poor English.

[Dayman]

[quote="nockdown"]
So the first question: Why can not qBittorrent check hash sum for several files at the same time?
[/quote]
Because it will be damn slow - random read access all over HDD. The only reasonable exception might be when content is stored on separate hard drives.

[nockdown]

Dayman, thank you for reply. Ok!

And how about second question?

Why does qBittorrent sometimes begin to download instead of hash in spite of such file is already exists on hard drive on needed location with needed name?

[Dayman]

Are you by any chance downloading torrents, which are constantly being updated (like files being added/removed/changed)?

[nockdown]

Yes, file names were changed. After new installation of operating system I would like to add files to seeding.

So I manually choose locations and files (file names) for hashing for torrents. If I do it one by one - everything is OK, but if I do it at the same time (while one file is still hashing) qBittorrent begins to download instead of hash file in queue.