I have a Realtek 8111C network card in my HP Pavilion Elite m9180a, there's only been one kext that's worked for me since I started using Yosemite and that is RealtekR1000SL.kext. It's not very stable though and randomly disconnects however this does resolve itself after restarting my PC.
I'm using Clover and have my own DSDT and SSDT specific to my PC, although after adding RealtekRTL8111.kext to my Clover's 10.11 folder and deleting RealtekR1000SL.kext, the Ethernet connection in System Preferences just says Ethernet is not connected. I've tried removing the Ethernet profile from System Preferences prior to restarting my PC too - no luck yet.
Any ideas why I can't get this to work?