All the relevant specs are in the signature.
i7-2600k should do quite well. GTX970 should be able to run WoW with any settings.
Raiding is pretty complicated, a lot of stuff going on. It all has to be calculated by the CPU, who is standing where, area of effect radius, and all kinds of things. If you see no change by reducing graphics settings, then it is a CPU issue. Not really much to be done, except possibly overclocking the CPU. WoW is an old game engine, it basically runs everything on a single core.