# Beryl 7 (GL-MT3600BE) - TX speeds unstable

**URL:** <https://forum.gl-inet.com/t/beryl-7-gl-mt3600be-tx-speeds-unstable/67283>\
**Category:** Router\
**Created:** [February 22, 2026, 7:00pm UTC](https://forum.gl-inet.com/t/beryl-7-gl-mt3600be-tx-speeds-unstable/67283 "2026-02-22T19:00:06Z")\
**Posts on this page:** 1\
**Showing post:** 23

<div class="post-metadata">

**Author:** ![oorweeg](https://forum-assets.gl-inet.com/letter_avatar_proxy/v4/letter/o/b782af/32.png) [@oorweeg](https://forum.gl-inet.com/u/oorweeg)\
**Post date:** [March 1, 2026, 7:14pm UTC](https://forum.gl-inet.com/t/beryl-7-gl-mt3600be-tx-speeds-unstable/67283/23 "2026-03-01T19:14:33Z")

</div>

Status update. You can completely disregard my earlier findings. The issue was with the test client I was using on the VLAN tagged side. When adding a VLAN tag the NIC didn’t automatically adjust the MTU correctly so was discarding input frames. 🙄

Manually forcing a higher MTU to account for the additional VLAN overhead resolved the issue and I cant get the same speed results I was seeing before lowering the MTU on the Beryl.

Back to square one and can’t reproduce your issues on my unit so something else is at play in your case ☹

---

_[View the full topic](https://forum.gl-inet.com/t/beryl-7-gl-mt3600be-tx-speeds-unstable/67283)._