Radeon PCI Express / PCI card problem

Anyone have experience of the Intel 915GAG motherboard with the 915
chipset, running a PCI graphics card with either the onboard video or a
PCI Express card?

We tested out various configs of these, but we couldn't get a stable
system. I'm thinking either the motherboard, chipset or PCI Express is
unstable and I should be going for an 845 chipset board with no PCI
Express.