I noticed this happening in the last days. It happens even with minimal graphics settings, windowed too. Specs are i5 4460, 8gb ddr3, asus 960 4gb 1680x1050 seasonic 620w gigayte b85 mobo. Got latest nvidia drivers and it's the same. Happens rarely so the game is still very playable. Happens in dalaran or when fighting a mob outside or flying or leaving a portal. Not happening when leveling my alts tho idk why even on mage porting all the time. Same addons on both, just different accounts. I went on the strand bg and there after first fight started my game chokes, frame changing only every 5-10sec. Chokes always when I loot something.
Also noticed that sometimes if I play wow for long and I close my game I see that my temps and fan speed are still the same even after a minute or two ( with the wow process certainly killed) - the load being still minimal like 150 gpu ram used - or 1 time my gpu fan made a weird noise like it's touching something ( all clean tho) with fan speed suddenly jumping up and down like 10% and temps 5* until I restart the machine. Temps and fan are never above 60* 30% usually 47 with 20
using old wow version with no modifications - vsync on
haven't noticed that choking in other games ( except in mafia 3 but that one is a **** port)