Why does it lag so much on the ground?

[AmberJoyBliss]

My draw distance is set to 64m, but still, when I am on the ground, everything lags a lot more.

I only visit the ground when necessary, but for me, SL is a skybox world.

[Alwin Alcott]

depends mostly on your system, and preference settings.
If you want to get, possibly, more advice it would help a lot when you post your viewer info here, you find it in help/about 
copy/paste it here
 

[Qie Niangao]

Certainly the ground has a lot more to draw, even with only a short draw distance, and a lot more that's excluded from drawing by occlusion of other stuff in the way.

Also, if you're anywhere near Linden water, that's just a nightmare of rendering complexity in pre-PBR viewers. The terrain mesh is no picnic either.

[AmeliaJ08]

Presumably you've got your settings too high for your hardware. Without any information though it's hard to tell!

Post the output of Help > About to provide some information.

[Jackson Redstar]

I keep set max 512 on textures option (found in settings) also maybe find or make a decent light setting that everything looks ok still with no shadows on - I used to do that when I had a much weaker machine.  Also if on FS make sure the Dynamic Draw is on in the PhotoTools panel,  As far as why I suppose it is just because there is more stuff that has to be rendered

[gwynchisholm]

It’s due to the large network of underground mole dwellings you’re rendering underneath the terrain mesh.

[sandi Mexicola]

Is it laggy on the ground everywhere, or only in some places?

[rasterscan]

7 hours ago, sandi Mexicola said:

Is it laggy on the ground everywhere, or only in some places?

Some places seem worse than others maybe its my pc

[sandi Mexicola]

Probably I would suggest reducing your draw distance when you are in laggy places.  Ground-level in some places is sometimes crowded with tons of objects.