Running OS: Windows 8.1 x64
Tixati Version: 2.51

I'm Tixati rookie.

I found that Tixati makes a lot of fragmentation compared to other clients.

Defraggler Screenshot: http://imgur.com/a/KKQMK
(!TX = Tixati Pre-Allocate File, !QT = qBitTorrent Pre-Allocate File)

I used Tixati option. "Fast Allocation" option created more fragmentation than "Full Pre-Write" option.

Windows operating system manages fragmentation automatically.
To do so, set the block size as large as possible when writing system call.
Fragmentation occurs when writing small blocks.
Call WriteFile() or SetFilePointer() only once when Pre-Allocate.

uTorrent and qBitTorrent is not occurred this problems.

Thanks for reading. Happy new year.

You should use Sparse Files as it will do best of both worlds
If you File System doesn't support Sparse Files I would consider changing.

I had the problem too... some videos I couldnt even stream anymore because file i/o was so bad due to fragmentation.

What I did was setup a post finish command in tixati to run sysinternals "contig" command on the file... brings fragmentation down from 20k to 1...

"Sparse" is not best ways.
Sparse makes file fragmenation.
File fragmentation accelerates disk fragmentation.
If we only use the Sparse option, there is no reason for the Full-Alloc option to exist.

References:
https://en.wikipedia.org/wiki/Sparse_file  - Disadvantage

In my opinion, file fragmentation is not that important. It is a disadvantage for files that are often used and most files downloaded with torrents aren't. I think a good idea is to make separate partition just for downloaded files and never defragment that partition.

I use for torrent a separate NTFS partition 890 Gb (completely defragmented, 50% free). Win7 x86. I download movies on average 1,5-4 Gb. Tixati creates very large fragmentation 0,5-1 megabytes per fragment. Then even MediaInfo on the file opens a several
seconds. File Allocation settings do not affect (except that Full Pre-Write starts very slowly). In utorrent there is no such problem. And Explorer/Total Commander almost does not create fragmentation when copying. In Tixati is very inefficient mechanism for the distribution of files. Please correct this.

I often use downloaded files. I watch movies, process video.

This problem has not been solved yet. Fragmented files need more than twice the time to copy and move than non-files.
My file has an average copy rate of 100MB/s. A fragmented file has a copy rate of 30MB/s or less.

The problem is that when the free space of a disk is fragmented, it causes fragmentation to a file rather than a torrent, which causes a heavy load on the hard disk if it is continuously fragmented.

That's why programs such as uTorrent and qBittorrent prevent fragmentation through Pre-Write functionality.

Using SSD solves the problem, but it is not pleasant to waste the life of a small and expensive SSD for torrent downloading.

When the FastCopy utility or the TeraCopy utility copies files, see what it does to prevent fragmentation.
The FastCopy utility uses the GPL license, so you can view the source.