My guild has had issues with something similar to this the last few weeks. Some information I’ve gathered from the issue which we have experienced on our consistent raid nights from 7:00 PST - 10:30 PST tues/thurs:
- The lag primarily manifests in stuttered rendering/delayed ability usage, generally stuttering every second or so.
- This lag only occurs in Castle Nathria. None of us are experiencing this issue (visibly) outside the raid, even in other instanced content.
- The first time we observed this issue was Tuesday Dec 29th from 7:00 - 10:30 PST. Since that date we have observed the problem as a raid group on every Tuesday/Thursday night at the same time.
- Some fights are better/worse than others. The beginning of Sire Denathrius is particularly bad (all 3 weeks) while other fights like Huntsman Altimore are much less severe - even to the point where some of our players no longer notice the issue.
- This issue does not seem to be at the same severity for each person experiencing it, some members only have minor stuttering while others describe their performance as “a slide show”.
- We could not determine any hardware similarities between members of our team having the issue (some have Nvidia cards while others have AMD, some have WoW on an SSD while others do not, etc).
- Disabling all addons had no effect on the issue.
- Reducing graphical settings had no effect on the issue.
- Reinstalling the game had no effect on the issue.
- The lag feels consistently less severe on Thursday night (7:00-10:30 PST) than on Tuesday nights (7:00-10:30 PST).
- The lag was present in both Normal and Heroic. I have not been able to experience the lag in LFR, even minutes following experiencing it in my guilds raid (although with a different raid group via the group finder).
- WinMTR reports run against 137.221.105.2 (the US West IP provided on the battle.net page for troubleshooting internet issues) during the raid showed 0% packet loss and an average ping of 40 across our entire raid night (7:00 -10:30 PST on January 19th). This is quite close to my usual ping outside of raid which usually sits at around 37ms.
EDIT: Some additional things worth mentioning:
- All members of our group are from the Lightbringer-US server.
- Our group size has been very consistently between 20 and 25 players. The exact amount hasn’t seemed to impact the issue.
- The issue typically only occurs during combat. Once combat is over it usually vanishes entirely.
Thanks for looking into the issue and hopefully you can fix it soon - it makes our warriors very sad.