|The Radeon 9000 viideo chipset supports 2X /4X / 8X AGP modes|
The GX270 series specs
has the Intel 865G chipset
8x /4x AGP modes at 1.5 V
Apparently installing an AGP card that has a video chipset that supports 2X mode which uses 3.3v can DAMAGE the mboard that has the 865G main chipset and the video card !
see page 8
You need to use a card with a video chipset that does NOT support AGP 2X / 3.3v mode .
E.g. Radeon AGP chipsets and what AGP modes they support - scroll down: