Fenvi T919 - Bluetooth and WiFi choppy only on OSX?

Hi

I have a Fenvi T919 and I find the Bluetooth and WiFi (2.4G and 5G) choppy only on OSX. They're fine on Windows. I've read that it should work OOB and there's no kext for it. Whilst it does "work", it stutters. Fiddling with the antenna a bit improves things a bit, but not for long. Anyone know how to fix it?