AgentGOD,

something is not right with that util on my Club3D reference design HD4870X2. If I select 1,3V it warns me about setting a voltage higher than 1,45V lol.
If I still set it Rivatuner shows 1,59V VGPU for that core. Thankfully all HD4870X2 don't allow more than 1,35V to the core so it didn't kill my card, but you might want to look into that