kaery:Такое было в дреноре, в легионе подкрутили многопоточность и все 4 потока работают на 60-70% нагрузки. проблема точно не в нём.
Буквально пару дней назад общался с гмом по этому поводу, где они сами сказали, что как оно работало без многопотоков, так и работает.
Вот в принципе его ответ:
- спойлер
- Hi there Ярослав
Adam here from the support team, thanks for contacting me today about the CPU issues
Firstly thank you for sending in the files, I know they take a while to create but they are awesome in helping us identify causes of technical issues that sometimes are tricky to find without them.
I checked up on this and the way games will work with multi core CPUs is that they will always take up 1 core as a main, then overflow into the other cores if needed so they might have say 100/75/50/25% usage . there are of course some CPUs and versions of Windows that force an equal usage but that is sadly nothing to do with Blizzard 
There is one thing you might try, try adding '-cpubinding' to the command line in the launcher for WoW, that might force all cores to be used equally, but that is only as a last measure and might not work
There are also some posts on the forums with players with your concerns so you are not alone in any way, while we cnanot alter the game here please feel free to maybe add to the post with your input : http://us.battle.net/forums/en/wow/topic/20749417268" target="_blank
You can also tweet the devs directly using @warcraftdevs maybe they will be able to answer you fully on this matter. I would also make sure to visit our support page here: https://eu.battle.net/support/en/article/100525" target="_blank where you can check to see some improvement you can make on the Pc itself while awaiting an answer 
It was a pleasure to have helped you with this issue and can carry on now with no further issues
Stay safe
Коротко говоря, он заявляет, что ваув кушает 1 ядро на 100%, 2 на 75%, 3 на 50% и 4 на 25%. Но откровенно говоря это тупо неправда. Ибо работает 1 ядро на 60-90%, второе на 40-60%, а остальные вообще почти не грузятся (10-20%). И к слову это подтверждается кучей постов на офф форуме
П.С. проверенно на I5-750 (1156 socket) u Xeon E5440 (775 socket).
такая же история происходит если выставить частоту ядра в 700 Мгц, загрузка гпу в таком случае 99% и фпс в самой игре становится такой же как и на 1300 Мгц
