Yup, as smallg said, they will but only a very slightly, most of the time it's hardly noticeable.
I have noticed some scripts that cause issues though, the characters with the TGC fantasy pack really kill my FPS, just one on a map drops it quite a bit, I thought it was the model, but when I used one with the ai_neutral script there was no framerate hit at all. I think there's something in their AI scripts that's not quite right and it's draining resources.
i7, NV960 4GB, 16GB memory, 2x 4TB Hybrid, Win10.
i5 , AMD 6770 1GB, 8GB memory, 512GB Generic SATAIII + 2TB Seagate Baracuda SATAIII, Win7.
i3, Radeon integrated graphics, 4GB memory, 512gB Generic SATAII, Win8.1.
Q6600, Intel integrated graphics, 2GB memory, 180GB Generic SATAII, WinXP.