Msi Kt6 Delta wrong info On Agp ?

I Have a Msi Kt6 delta Mother board and when i run Aida32 (a system info Software) it shows to me that the Agp is Disabled which might cause performance problems . Now when i check it in my bios the AGP status is Auto and i cant change it to disabled or enabled . So what may be the problem ? wrong info by the software or is Agp really disabled ? The system works fine but some times its slow on 3d games .Agp = Winfast Fx5200 256
and one another thing that what value shall i give in the Agp aperture size ? My system ram is 256 the options are 4 8 16 32 64 128 and 256