Yes, your GPU is responsible for allowing you to play with high Internal Resolutions and various levels of AA. If your GPU can handle those settings, it won't become your system's bottleneck in Dolphin. Have you tried turning it down to 1x IR to see how that goes? Your GPU should be good for 4x IR, but if turning it down to 1x IR results in good speeds, we know the issue is with your GPU rather than your CPU.
Additionally, Nvidia GPUs were known to remain at idle clocks with Dolphin, which artificially created GPU bottlenecks when they weren't supposed to happen. Make sure you set your GPUs performance profile to Maximum Performance or whatever Nvidia calls it on Windows. Can you download a program called GPU-Z and take a screenshot of it while running Dolphin? For good measure, can you do the same, but with a program called CPU-Z as well?
Like xystus said, your settings look fine from where I'm standing. It's probably little hardware quirk, since you're definitely beefy enough to run Dolphin without these kinds of slowdowns.
Additionally, Nvidia GPUs were known to remain at idle clocks with Dolphin, which artificially created GPU bottlenecks when they weren't supposed to happen. Make sure you set your GPUs performance profile to Maximum Performance or whatever Nvidia calls it on Windows. Can you download a program called GPU-Z and take a screenshot of it while running Dolphin? For good measure, can you do the same, but with a program called CPU-Z as well?
Like xystus said, your settings look fine from where I'm standing. It's probably little hardware quirk, since you're definitely beefy enough to run Dolphin without these kinds of slowdowns.