Throughput Drop on IPTV (Strong8k) with WireGuard/OpenVPN

[kevinhjl 0]

Hello all, relatively new user here loving the service, but I’ve hit a specific wall regarding IPTV performance.

Google TV Streamer 4K (hardwired 1GBps) connected to AirVPN via VPN Fusion on ASUS router (WireGuard/OpenVPN), analiti (speed test) shows speed of 400Mbps with and without VPN enabled. However, the moment I launch a stream, the bitrate collapses to below 100kBps. Without the VPN, the stream sustains 2-3Mbps without issue.

Appreciate any help I could get, thanks!

[ASiC666 4]

I have the exact same issue, no matter which server I'm using.
Did a lot of experimenting with different regions and servers to unfortunately bad results. 

I have a backup VPN just for this use case...

[Staff 10518]

22 hours ago, kevinhjl said:

analiti (speed test) shows speed of 400Mbps with VPN enabled. However, the moment I launch a stream, the bitrate collapses to below 100kBps

Hello!

Possible causes:

1. Streaming services (Netflix, YouTube, etc.) often rate-limit or deprioritize known VPN exit IP addresses, or IP addresses assigned to specific ASNs. Speed tests don’t trigger this, but video streams do. Try different AirVPN servers.
2. Too large virtual network interface MTU causing excessive fragmentation, optionally with broken MTU path discovery. Streaming uses sustained flows that are more sensitive to MTU mismatches than bursty speed tests. Shrink MTU to 1280 bytes to check whether you get any improvement. If not, consider MSS clamping, just in case the PMTU discovery is broken upstream (not an uncommon case). Set MSS to 40 bytes less than MTU, for example MTU 1320 bytes, MSS 1280 bytes. On Asus routers you'll need to do this via iptables: as far as we know there's no option to do it on the Web UI.
3. Asus Adaptive QoS or Bandwidth Limiter on the router. Check and disable such tools if they are active.
4. If DNS is outside the VPN but traffic is inside you can hit far-away CDN nodes, causing slow streams. Make sure to enforce strict DNS settings on the router so that it will query only VPN DNS.

Kind regards