This has been happening to me for a couple raid nights now. Around 8:30pm EST and 9:30pm EST (can be earlier or later), I've been getting lag spikes and 90k errors. This happens often once it starts and stops when I leave the Raid instance with lingering lag not as severe as the lag inside the instance. I've checked with my provider and they are saying things are ok on their end, and I have done multiple speed tests. I'll post some info below to help troubleshoot:

Character Name: Momeki Odgerel
Server: Hyperion
Service provider: Verizon
Download 80MBPs
Upload 40MBPs
10-11ms Latency
PC specs:
AMD Phenom(tm) II X4 910 Processor 2.6GHz
4GB RAM
GeForce GTX 650 Ti BOOST
64-bit Operating System
If anyone has more information that could possibly help or is having the same issues with more detail Please feel free to reply below as I try to find help for this. It's been really rough to deal with during raids when my connection is usually just fine.