How's the heat on it? Using a PC (desktop) with slightly higher specs than yours, but no problems on High settings. Heavy framedrops like that could mean your CPU is getting throttled due to overheating (based on my old laptop which was a 960M and i5-6700HQ)
Similarly, what settings are you running at? I'm sitting on a 2060 Super (slightly above 2070 in power), and can't get it above high if I want more than 30fps.
So yeah, two biggest things are temps and settings.