UI noticably slow on very high end machine since last update to 5.0.3

[Chaotikmind]

qBittorrent & operating system versions

qBittorrent: 5.0.3 x64
Operating system: Windows 10 Pro x64 (22H2) 19045.5247
System : I9-13900ks, 64gb ddr5 6000, 6tb nvme, rtx 4090

What is the problem?

As i said in the title, since i went from 4.X.X (i skipped some updates) , the ui wen noticably slower.

Nothing much else i can say, on my machine anything is usually instant.
my torrents are about 340 rigth now, more or less the same as before(actually it is probably lower than before since i did some cleaning)
1000 max connections / 200 per torrent / 20 max upload slots.

Unlike some of people i won't say it lag, but my machine can handle heavy load, but there is clearly a regression performance wise.

Regards.

Steps to reproduce

Use the software.

Additional context

I think it wouldn't not be very useful in that case.

Log(s) & preferences file(s)

n/a

[MarcusTerribilis]

I also notice a great slowness in downloads (qBittorrent 5.03). the flow rate seems divided by 4 or 5 compared to before.
I looked for solutions:

• I uninstalled the antivirus: same problem
• I checked the firewall rules: same problem
• I uninstalled then reinstalled the VPN (HideMe): same problem
• I uninstalled then reinstalled Qbittorrent: same problem
• I added a new network card to my computer: same problem
• I tried to change the DNS server addresses: same problem
• If I use another torrent software like "Transmission", the speed is OK (I have fiber optics)
• I tested qBittorrent on another machine (same network, same VPN, same torrents): the speed is OK

I don't understand why, but the problem seems to come from the software configuration of my computer (W11). The problem is not reproduced elsewhere. I am perplexed.

[Chaotikmind]

I also notice a great slowness in downloads (qBittorrent 5.03). the flow rate seems divided by 4 or 5 compared to before. I looked for solutions:

• I uninstalled the antivirus: same problem
• I checked the firewall rules: same problem
• I uninstalled then reinstalled the VPN (HideMe): same problem
• I uninstalled then reinstalled Qbittorrent: same problem
• I added a new network card to my computer: same problem
• I tried to change the DNS server addresses: same problem
• If I use another torrent software like "Transmission", the speed is OK (I have fiber optics)
• I tested qBittorrent on another machine (same network, same VPN, same torrents): the speed is OK

I don't understand why, but the problem seems to come from the software configuration of my computer (W11). The problem is not reproduced elsewhere. I am perplexed.

I'll check if i see any download performance degradation as well, my fiber connection is so good, that maybe i'll see nothing noticeable (8gbps here)

[vnicolici]

Did you use the regular version of 5.0.3 x64, or the qt6 lt20 version? The regular version uses libbittorrent 1.2. The other uses libbittorent 2.0 which has some performance issues that also impact the UI responsiveness. If you use the lt20 version, you could try enabling Simple pread/pwrite under advanced settings, which may improve performance. But in my experience it may still perform somewhat worse than the lt12 version, even with that setting.

[Chaotikmind]

Did you use the regular version of 5.0.3 x64, or the qt6 lt20 version? The regular version uses libbittorrent 1.2. The other uses libbittorent 2.0 which has some performance issues that also impact the UI responsiveness. If you use the lt20 version, you could try enabling Simple pread/pwrite under advanced settings, which may improve performance. But in my experience it may still perform somewhat worse than the lt12 version, even with that setting.

No it is the one using libtorrent 1.2