Low maximum transfer program limitation

Hi.
I have a gigabit internet connection. I have a hosting account with gigabit capability as well.
FlashFXP seems to have some maximum limitation of about 55MB/s in my tests (with about 35% CPU usage (thread)).
At the same time, with the same environment/server/test_file, another popular client is able to reach stable 85-90MB/s with about the same CPU usage. You can test above_100Mbps transfer speeds in in-house lab test scenario between two machines with gigabit router.
With all the UI goodies and advantages of FlashFXP, this is substantial speed difference.
I guess it just would need a bit of optimization of buffers or something..

Perhaps you could be a bit more specific, or give some actual details;
You may as well say "It doesn't work, now how do I fix it?"

What specific version of Windows OS are you using?

What specific version/build of FlashFXP were you using?

What anti-virus and/or firewall software/version are you using?

What is the server software/version?

What protocol are you connecting to the server with? FTP, FTPS, or SFTP.

If connecting using FTPS or SFTP then what cipher and strength, etc is being used?
(some ciphers are much faster than others; the default cipher order is based on strength and not speed.)

With SFTP latency is also an major issue, so what type of delay do you see when pinging the server IP?

Many performance changes were just recently made in 5.4.0.3952. Along with these improvements we also discovered some unexpected performance issues in the SFTP/encryption library we use (SecureBlackBox), Specifically I found that the es[128/256]-gcm and chacha20-poly1305 ciphers are slower than other libraries.

With SFTP you can adjust the cipher preference/order via the Site Manager > SFTP Tab.

With FTPS you can also adjust the cipher via the Site Manager > SSL Tab,
but you need to enter the cipher string in the OpenSSL format which is a bit more complicated.
https://www.openssl.org/docs/man1.1.0/apps/ciphers.html

[It seems the reply didn't go through the forum on first attempt..]
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I'm sorry, there are few other critical issues (lacks) in FXP that I cannot live with, so I'll be a bit laconic now but polite enough to answer.
Win7 x64 Enterprise, several builds of FXP 5.3, 5.4.
I just noticed FXP doesn't reach high speeds for me and if gigabit users are important, you could test more in such conditions anyway. It was not a bugreport or accusation etc. I have other types of programs (torrent clients as an example) where the contrast in maximum reachable above_100mb_speeds is also high. This is a factor for me if the difference is substantial. Most users won't notice anything because most ISPs are still 100 Mbit anyway. One torrent client reaches 40MB/s, the other is 70+, clearly the choice would be the second, no matter the UI or convenience. Nothing against the first, it was just an example. With torrents in particular, I've been testing all kind of settings for about 2 weeks to come to the final conclusion which client to stay with.

No antivirus software ever used by me since almost two decades. Firewall - is the built-in Win Firewall, with activated outgoing Block.
The server is on a hosting company, I don't know what is it, it's just a shared linux hosting. Ok, now I checked the log,
220---------- Welcome to Pure-FTPd [privsep] [TLS] ----------
The test file is 1.2GB, already cached in RAM after many tests.

When Explicit FTPS is selected for this profile, the maximum achievable speed by FXP is about 30MB/s. Tested many times in successsion, tests with other clients were in succession too after and before FXP tests.
When I switch to *plain FTP*, the limit is the abovementioned about 55MB/s max. CPU load is about 35-40% (single core load).
The other client (the most popular free one) achieves 90+MB/s (now I tested again, 98MB/s, also plain FTP), using ~25% cpu. Switching it to FTPS results in ~70MB/s. Either way, the difference is twice the rate of FXP.
I don't use SFTP with this hosting account. So, the conditions are equal, the encryption plays a role by lowering the speed in both clients. That's why I do parallel (one after the other of course) tests with other clients, same test file, plain FTP etc.

I just wanted to pay attention that FXP is a very good program, but for now, it doesn't seem quite on par with some others in gigabit connection circumstances, and this is where it could be improved once gigabit becomes widespread.
No worries - to achieve sustainable gigabit transfer rates is not quite trivial, this is for sure. I guess FXP is ideal for maybe 95% of the users.
I didn't test latest few builds, but for now I'm not motivated to do it because of the other lacks in the program (lack of true background transfers allowing to independently browse the FTP, and the tree/list "fireworks" while transferring many folders and files) which seem critical to me, sorry.