You should not go for a new CPU/mobo if you mostly just play WoW with that computer.
You cannot Xfire your raids because your hdd is slow, not because of your CPU.
1080p recording needs up to 70mb/s write speed, your 5 years old hdd that has the WoW + Windows running on it while recording to it just cant handle it.
Go for a Samsung Spinpoint F3, (maybe two and record to the other one).
Also you could buy a nice CPU cooler and overclock your CPU.
| Ryzen R7 5800X | Radeon RX 6800 |