Flint 2 – Significant VPN performance drop and higher memory usage after upgrading to 4.9.0

Router
1

Hi,

I recently upgraded my Flint 2 to firmware 4.9.0 and have noticed issues compared to the previous firmware (4.8.3).

WireGuard VPN performance drop

Before upgrading, I consistently achieved around 600 Mbps download and upload through ProtonVPN using WireGuard.

After upgrading to 4.9.0, VPN performance changed significantly:

  • Download: approximately 250 Mbps

  • Upload: approximately 400 Mbps

During troubleshooting, I found that disabling Network Acceleration increased download speed to around 390 Mbps, but this is still considerably lower than the ~600 Mbps I achieved before the upgrade.

My setup:

  • Router: Flint 2 (MT6000)

  • Firmware: 4.9.0

  • VPN Provider: ProtonVPN

  • Protocol: WireGuard

I performed a clean installation of 4.9.0 and did not restore any previous settings or configuration backups.

Also WIFI strength have been noticeably lowered, in a small apartment (3 of 4 strength on wifi, 4 meters from router).

Increased memory usage with AdGuard Home

Before update, memory usage was around 38%.

After update, memory usage increased to around 60%:

  • HaGeZi Pro++

  • AdGuard DNS Popup Hosts

  • HaGeZi Windows/Office Tracker

  • Local DNS filter list (small)

  • HaGeZi Threat Intelligence Feeds

This appears noticeably higher than what I experienced on previous firmware versions.

  1. Has anything changed in firmware 4.9.0 that could affect WireGuard throughput or Network Acceleration?

  2. Is the increased memory usage with AdGuard Home expected in 4.9.0?

  3. Are there any recommended settings or optimizations to restore previous VPN performance?

Thank you!

2

Overlapping lists in your Adguard filters can increase memory and CPU filtering overheads.
HaGeZi Pro++ already includes:

Ads / tracking / malware
Phishing + scam domains
Telemetry lists
Multiple specialised sub-lists (including popup / annoyance coverage depending on version)

Likely to overlap with the Adguard DND Popup Hosts which isn’t really needed with Pro++.

Your Windows / Office Tracker is quite a strict blocker and likely to break activation checks, login and updates, so as long as you’re aware. The HaGeZi Pro++ has some office tracking included but not as much as the specific HaGeZi Windows/Office Tracker list.

Can’t really comment on Proton VPN, as I use Surfshark and get incredible speeds for a VPN (currently 748.2 Mbps), so maybe try a different server and device for speed checking?

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4

I found the slow VPN speeds is because of the huge drop of WIFI coverage. If I place a phone on the router I get close to 600 mbps. Behind a wooden door 4 meters away it waaay lower. Glinet needs to do something about this extremely low WiFi coverage I’ve seen lots of post about.