When I have lag greatter than 300 I generally do the following
1. completely log out and restart the character
2. reboot my modems
3. test my internet lag with http://www.speedtest.net/
4. restart computers, WiFi, check router settings.
5. have a long chat with my ISP
6. try a back up modem and see if old modem has bit the dust. Some makes of modems communicate better with your ISP than others. For my ISP I find Broadcom chips just work better.
If all characters have the same lag then logging out and restarting probably will do nothing. But if I have something like
210 210 233 225 240 and 780 then I know something is wrong with the the 780 character and I log out and back in again. (this does happen far more often now with the new code and windows 10....haven't found the cause of it).
Another forum post deals with CPU parking. Should make sure all are not parked. If you have enough cores available, might leave 1 free for the machine and use the rest for EQ.
Cthulio got me started on the importance of replacing a modem, router, switch all in one device from your isp with a dedicated modem, a dedicated router, and a dedicated switch. Here's a pair of good write ups on the topic:
http://www.smallnetbuilder.com/lanwan/l ... nce-part-1
http://www.smallnetbuilder.com/basics/l ... nce-part-2
I have used CFosSpeed on and off for years. Doesn't seem to help currently but then, I now have a pretty advanced router that has overlapping abilities with CFosSpeed. CFosSpeed can be tried for free and has pointers on how to reduce lag:
https://www.cfos.de/en/cfosspeed/docume ... track_pv=1
What MIGHT be nice for US Players on THF would be some way of setting up a pipe twixt the server and the US. This exceeds my current knowledge but I've read such a thing is possible. Something like a remote gateway or VPN US players could hook into to reduce hops.