I was about to create another thread, since OP is having a lot of issues, but I'll just try to focus on one:

- random/sporadic lag spikes causing banding issues
This is the most recent, and the worst culprit. Started around Jan 9th/10th (I think). This happens mainly in dungeons and instances (doesn't really lag in the overworld, except for when I'm retrieving retainers...?”. Take today for example: was running Turn10. No other PT members (all on my server) experienced any lag. Yet, throughout the fight (notably when the adds spawn) I will get lag spikes lasting 3-10 seconds (everything will stop on the screen, then speed up and catch up; “banding”). We did ~10 runs total, and this happened 7-8 of them. Random time during the fights, random downtime durations, etc. Also, went running an EX dungeon, had banding issues all throughout. Then capped the night with a ShivaEX farm, but kept banding all over the fight.
Same problem, started last week. It's not new for me, sometimes it happens but usually it's not so often and agressive as it's beeing this week.

And I can't figure out the reason, since:

1st Suspect, Internet: I play on my Notebook and my Girfriend on a PS4. Same internet connection, only I was having the problem;
2nd Suspect, Hardware: A friend from my static was having the same problem on his PC, and tried to switch to PS4. Same problem.

Anyone have experienced this issue? It cost us or training on T13 last night =/