No.
5970, although a good card with dual GPUs, awesome for gaming, SUCK ASS for mining.
You cannot crack MSI Afterburner using them. Which means you cannot underclock the memory or overclock the core very much.
You are better off getting two 5850s and over clocking the HELL out of those. That is basically what a 5970 is. Two 5850s but I would rather have two 5850s ANY DAY over 1 5970.
what a bullshit... I have 3x5970 in 1 mining rig. The Afterburner overclock them _perfectly_. Even if you have any troubles with overclocking you still could modify the BIOSes with overclocked settings so it will be there are no any need in overclocking software at all...