Sometimes it was needed to run LFS installer with admin priviledges too.
I would not say 20fps to be smooth at all, 40 is quite low also, stable 60fps is smooth, imo. However that is quite subjective definition and it means different to different people.
I prefer that fps don't fluctuate so I like to limit it to lowest, but that is not possible in this machine as fps do drop so much. Only 24fps when alone on track passing BL1 pits, with 6 cars and back of rid it is under 15fps at best, maybe it is just normal fot Sempron 64 3400+ and radeon 1100 as 3d benchmarks show up numbers that they should.