Having a problem with the game

Hello i'v been having an fps problem with the game for the past few days i used to play normally without any lag issue but lately when ever i join an icc25 or any 25 raid i'd get a crazy lag and drop fps and the game starts using 100% of my cpu even though before when i launch it while i am calling in discord and using google it doesnt even take 50% of my cpu but now just launching it alone takes 88%+ of my cpu can you help me please i dont know why its like this and its only like this in wow when i play another game i dont lag at all i dont get any drop fps everything is normal pls help me

Do you use WotLK client with WoD models or (old)?
What addons are you running?
Have you lately updated drivers, changed PC settings? When was the last you've done either?

i am using the old one my addons are : auctionator/DBM/Pallypower/Recount/Omen/Weakaura
and no i didnt change any pc settings or updated anything if i update anything in my pc it would ruin my ram and last time i reinstalled my window was 6 months ago at the same time i downloaded world of warcraft

this started recently for me as well...but much worse. any combat, one MOB or more, results in stuttery frame rate - I mean like 2 - 3 FPS. As soon as combat ends, it goes back to my normal 100+ FPS. It does not mater if im in the world, a dungeon, or a raid. This happens on 3 separate PC's in my house. Our net connection is 400 MBPS and our latency here is around 150 MS. I've never had this problem until about a week or so ago. It happens on Frostmourn and Icecrown for sure (have not checked the other servers). It's basically unplayable (this after I dropped $40 USD on two accounts in the store...great).

point of note: this does not happen on any other game and I'm pretty sure all three of my PC's are not dying at the same time.

thats the same problem i have for me it happens on icecrown only :/