high cpu load

i noticed a high cpu load in version 4.4 when large files are transferred. the flashfxp.exe process causes up to 25% cpu load on an i5 3xxx. almost takes up one core completely. normally cpu load would be ~2%. i tried to change the tcp buffer sizes. but to no avail.
reported to same bug a few years ago, which was fixed in a new version.

What specific version of Windows are you using?

What type of transfer, FTP, FTPS, or SFTP?

In what direction are you transferring, upload, download, or FXP?

Are you transferring to/from a USB flash drive, or network share? If yes then which?

Are you using a proxy server? If yes what type of proxy server SOCKS4, SOCKS5, FTP Proxy, HTTP Proxy? Is the proxy local?

Are you using a software firewall? If yes then which one, and what version?

Have you tried using the default TCP/IP buffer size?

When the cpu usage is high what speed are you getting within FlashFXP?

What specific version of Windows are you using?
win 7
What type of transfer, FTP, FTPS, or SFTP?
FTP
In what direction are you transferring, upload, download, or FXP?
upload to local NAS
Are you transferring to/from a USB flash drive, or network share? If yes then which?
No, from internal HDD
Are you using a proxy server? If yes what type of proxy server SOCKS4, SOCKS5, FTP Proxy, HTTP Proxy? Is the proxy local?
no
Are you using a software firewall? If yes then which one, and what version?
built-in windows firewall
Have you tried using the default TCP/IP buffer size?
yes
When the cpu usage is high what speed are you getting within FlashFXP?
55mb/s (the limit of the NAS)

I forgot to ask you what specific build of v4.4 are you using?

Do you recall what version/build of FlashFXP you upgraded from?

All previous builds can downloaded from our website if you want to try an older release.
http://archive.flashfxp.com/archives/

I conducted some tests using the latest v4.4 build (2044) and based on the results I am not seeing anything abnormal about the cpu usage.

A few things to consider which might attribute to the high cpu load.

1. If the file being transferred is highly fragmented this can increase the time it takes for each read operation and can increase the cpu usage.

2. Windows Defender (or any anti-virus, malware scanner) with real-time protection/scanning can increase the cpu usage of the application that is accessing the file.

3. If too many programs are reading/writing to the drive where the file is located or if the drive contains a temp file such as windows pagesys.sys or hiberfil.sys this can create a bottleneck and increase cpu load.

4. Sometimes rebooting can resolve unusually high cpu load.

did a check with some older builds and I'm getting the same CPU load. so its probably something specific to my PC.
the ticket can be closed.
thank you for your support.

EDIT: one last question: is the CPU load i described abnormal in your experience ? should i follow up on this and maybe reinstall the OS ? or is this kind of CPU load to be expected considering the circumstances.

I would recommend running disk defragmentation tool on your drive and see if this reduces your cpu load and go from there.