Technical FPS Drop

[Juggernaught]

Hello,

I'm running MoP on an i7 @2.20GHZ, 6GB RAM, and Nvidia GeForce GT 540M, Win 8 64 Bit.

I usually have around 47-60 FPS in the cities like Orgrimmar, or Shrine of Two Moons, which is really fine, but once I join a ToT 25 man raid, FPS drops to 1-2 and it's unplayable, I've searched the internet over and over and I haven't found a solution, my PC is a year or 2 old, there must be something I'm missing, some kind of fix, or some settings change, I'd like your help thanks. I can post my DxDiag for people who understand.

[xRockBoy]

Try disabling shadows in-game.

[Juggernaught]

Try disabling shadows in-game.

Tried everything related to the in game settings, even my nvidia settings.

[xRockBoy]

Run as administrator/change compatibillity or try making another administrator account and play from there, maybe you have something in background that opens when you turn on the pc (msconfig).