Previously, uTorrent hashed even 250 GB distributions instantly, and now it hashes 3 GB every 10 minutes. What happened?

Question

Windows

After installing the new Windows 10, uTorrent was flying! And now, two months later, the hashing of the weakest distribution from my collection is barely pulling. Why?
• OS: Windows 10;
• RAM: 32 Gb;
• SSD: 256 Gb;
• uTorrent version: Pro 3.4.5 (41372).
I didn't install any new software, only Assassin's Creed: Syndicate from heavy programs. I did not change the settings in uTorrent.

Answer 1

Previously, uTorrent hashed even 250 GB downloads instantly.

To hash 250GB, you need to at least read these 250GB and calculate the hash. It is impossible to do this instantly, and it is difficult to do it quickly.

And now, two months later, the hashing of the weakest distribution from my collection is barely pulling. Why?

Not enough information to say anything.
We need to look at what the problem is, perhaps some kind of antivirus, or crooked settings.
Yes, and it is not clear what it means to barely pull? More precisely, it is necessary to speak.

Answer 2

In the bearded years, DC++ had a great option to store hashes of files in their file streams. That's when everything was hashed instantly, due to the fact that instead of a file it was possible to read the hash that had already been calculated earlier.
For torrent clients, this does not make much sense - there, hashing is needed mainly to check the integrity, which means that the entire file must be read this way and that.
Hashing always goes at maximum speed, i.e. clogs i / o disk reading by 100%. Because for a processor, 50-500 mb / s of a file stream is generally invisible, and it does not limit this matter in any way.
So if the hash rate is low - first of all, you need to conduct a linear disk read test. Maybe he's dying?
If the cache is small - hashing can share access to the disk with downloads / distributions, slowing down by 3-4 times, but only on hdd. On ssd, this is imperceptible in principle.
The solution is to set the cache to autosize, or increase the cache if it is not rubber (of a constant size), and disable forced flushing of the cache to disk (the task of the cache is to delay the write as long as possible), otherwise each completed block will interrupt hashing for the duration of the write, and when 100Mbit/s stream, 4kb blocks and hdd is loading i/o recording stream from 25 to 100%.
With torrents and Windows, there is another trick: a large degree of fragmentation. With incorrect settings (and this is 95% of users), a clogged disk (the presence of micro-windows from free clusters) and the inability to properly distribute space for files (and these are all versions of Windows), we get monstrous fragmentation at the output: 30-50k fragments per 4GB image is the norm .
Such strong fragmentation slows down reading, very much on hdd, and noticeable on ssd: even ssd has an iops limit, and it's not that big, the difference in read time can reach 200% on ssd and over 9000% on hdd.
So slow hashing is also a signal to check the level of fragmentation of files of interest. If it is high, you should eliminate fragmentation (even on ssd!), and reconfigure the torrent client correctly.
Well, for dozens, in particular, a bug with slow access to files is characteristic. There are posts about this on the net. I don’t know why, but 10 turned out to be slower than 7 and 8.
There is no solution.
Plus, all this can be superimposed by a problem with caches.
In all torrent clients, the system cache needs to be disabled - operating systems do not know how to work with torrents, they do not distinguish between contexts, they start loading files at their request into memory indiscriminately, which causes an unnecessary overhead.
If in the top ten they screwed up with the caching subsystem, this could further aggravate the overhead, which is not so noticeable on other versions of Windows.
The solution is to turn off the OS from work by setting the appropriate options in the client settings.

Answer 3

As far as I understand, about a year ago, in the mutorrent, the diskio.sparce_files option became true by default, and since this option causes the wildest file fragmentation, the low caching speed is understandable.
PS I once said to the mutorrent, oh, everything took up its fundamental finishing and finishing so that it was "for people", as a result, here https://toster.ru/answer?answer_id=467299#answers_...
PPS I propose my assembly because in the settings assembly and this point is already fixed too.

Answer 4

Apparently - "earlier" - before the introduction of the newfangled 3rd line of uTorrent.
She cunningly accustomed you to advertising, which takes up some of the computer's resources :)