You have to install the fakeSMC GPU plugin to monitor it. The version that's part of multibeast that i had installed caused crashes with my GTX1080. There are newer versions and other branches. I use istat for the actual monitoring.
I just tried my GTX 1070. I couldn't even boot with FakeSMC GPUSensors kext (at Clover/kexts/Other). Tried latest hwsensors.com and rehabman versions. Kernel panic during boot, conflicting with IOPCIFamily.kext. Used to work with my GTX 980. I had to remove GPUSensors kext to make it to desktop.