I have an old config, Q9650+MSI P35 Neo2-FR and received 2x R7 240.
The videocards work in crossfire on a Q57 and a Z77, but not on P35.
GPU-Z sees the cards at PCIEx 1.1 x16 respectively X4. However, on the P35 system the Crossfire option does not appear in the Adrenalin driver. If I move the cards and the same HDD on the newer platforms, the option appears immediately.
Is PCIEx 1.1 too slow for these entry level cards ? I don't think so. I had fun installing one of them sepparately on a x1 to x16 riser and there was almost no frame drop in some games. Therefore the GPU is too slow even for x1.
Could you please help me how to enable it?