We do not claim compatibility with G3 upgrade cards since there are many cards available that can work with so many different computer configurations. Many customers do invest in G3 upgrade cards and they do get a large increase in performance from the processor as expected. We haven't had any major conflicts reported by users with G3 upgrade cards and in general, they do serve their purpose. If you invest in an upgrade card we recommend getting some sort of return policy. If the card doesn't provide the increase in performance you were looking for, or you do encounter any problems, you can return then return the card. If you do encounter any problems you should contact Technical Support.