Default [Q] some questions about huawei g600 (u8950-1)

Hello everyone!

So, my device is Huawei G600 (U8950-1) and it really a good phone . However, I have encountered some problems with my phone, it's launcher and the UI is laggy (not smooth in swiping,switching launcher pages and scrolling) , and sometimes my phone restarts immediately with no signs especially when playing games or it gets hot (not too much).
So my question is , does upgrading my firmware to this firmware : will fix the laggy and the random restarts of my phone?
AND also , does flashing to a official firmware requires an unlock bootloader?

Thanks in advanced !
(im sorry for my bad english ,i'm not an english speaking person )