Technical Huge Lag on Boss Fights

[ZlaGad]

Hello Guys,
As the topic suggests, I have a massive lag on boss fights.
Have an offscreen working browser without any problem, which automatically excludes problems with the internet connection.
Do you have a similar/same experience?

[OhieMitzen]

Try disabling Recount/Skada/Details, see if it helps.

If none of those were the cause, try without any addons next. Then it's process of elimination if it's caused by an addon.

[ZlaGad]

Have only GearScore.

[OhieMitzen]

Try without, to rule out any addon interference.

After that's ruled out, connection troubleshooting might be in order.

And just to be sure, when you say lag on boss fights, you mean internet lag (high ms) and not FPS being low?

[ZlaGad]

Yes, I have a high lag (between 1000 and 4000 ms), which makes playing impossible. After the raid (except for me), kill the boss, and the lag goes down. I'm able to play normally until the next boss. At this time, I'm on Discord and can hear people talking without any delay (which excludes any internet issues).
No problems at all with FPS
I disabled GearScore, and this problem still exists.
Could you tell me what to do?

[Shred]

Make sure your netowrk adapter drivers are up to date, that your router software is up to date (if applicable) and well configured, that you don't have any weird firewall/antivirus software running, if you are using wifi try connecting with cable, if you must use wifi try changing the channel