I think you've got the CPU clock override setup in the wrong direction. Increasing that value means you're overclocking the GC CPU, and increasing the work your computer is trying emulate. If you set it back to 100% does it run faster/without lag?
Check your CPU: Open Windows Task Manager when running Dolphin (or some other Hw monitoring software) to make sure your CPU isn't downclocking itself. Check window's Power management and max sure it's set to "High Performance".
Check your GPU: Go into the Nvidia Control Panel > 3D Settings > Manage 3D Settings > Program Settings tab > make a profile for Dolphin > set the Power management mode to " Prefer maximum performance" so that your GPU isn't downclocking itself.
Check your CPU: Open Windows Task Manager when running Dolphin (or some other Hw monitoring software) to make sure your CPU isn't downclocking itself. Check window's Power management and max sure it's set to "High Performance".
Check your GPU: Go into the Nvidia Control Panel > 3D Settings > Manage 3D Settings > Program Settings tab > make a profile for Dolphin > set the Power management mode to " Prefer maximum performance" so that your GPU isn't downclocking itself.