different audio play / record volume level (windows xp, ms..

I have an MSI 645EMAx2 Series main board based on SiS 645X chipset
with Realtek AC'97 ALC 650 v2.2. (Driver 5.10.0.5100) and use Window
XP SP1 Home Edition.

I connect something (VCR/Rec-Out/etc.) to the line in port of the main
port.

In the windows volume control window I can set the Play Volume with
the slider and get a good result by setting the slider 3/7 from bottom
of the bar.

However in Record Volume part I have to set the slider to almost 0/7
from the bottom other wise the audio will record four two load, i.e.
some applications will clip. Note I still use the same source with the
same input level. Why this difference? I've tested several
applications and it's all the same? What can I do about that?