Performance in SP compared to MP?

[w3tw1lly]

SP Has:

1) More bipeds running around with attached AI
2) Larger BSPs
3) Even more detail to go along with the larger bsp
4) h4x
5) Cortana

'nuf said

Yeah I know but Half-Life 2 runs way better in SP than in MP for me so that is why I am wondering. It would make sense for performance to be better in MP but I have seen otherwise.