When shaders are off in OpenGL, some things aren't culled.

Using Debian 10, on a nVidia GeForce 660, official nVidia drivers

goldentails@debian-desktop:~/GoldenTailsSRB2$ lsmod | grep nvidia
nvidia_drm             49152  4
drm_kms_helper        208896  1 nvidia_drm
drm                   495616  7 drm_kms_helper,nvidia_drm
nvidia_modeset       1097728  9 nvidia_drm
nvidia              18247680  327 nvidia_modeset
ipmi_msghandler        65536  2 ipmi_devintf,nvidia