FPS

As of version 4.0, LagGoggles provides a way to measure FPS on the client, you don't need LagGoggles installed on the server for this to work.

You can start the FPS measurement by clicking the 'profile for # seconds' button. You will be prompted to choose World or FPS, choose FPS.

You will be prompted not to look around while profiling FPS. This is due to the fact that your client only loads entities if you look in their general direction. If you wish to profile a single entity, you should keep that entity in your sight at all times to get a proper measurement.

Limitations

1. Because of my limited understanding of how rendering in clients work, I was unable to find the time it takes to draw a block. So at this moment blocks are not being checked, I think they are buffered when the world loads on the client, and then redrawn again and again using that buffer (Quads). If you can figure out how to time rendering a block, let me know!
2. Not all mods render objects the same way, some use events (Like LagGoggles!), and other use custom models tucked away in the mod, or a .json file somewhere.