On [H]ardForum, a kind user worked out for me a year ago the Handbrake performance comparison of a dual X5670 with some of the fastest consumer CPUs at that time: https://hardforum.com/threads/replacing-dual-x5670.1963388/#... turned out the 2700X is 1.95 times as fast in Handbrake as a single X5670.
Not after you price the power. I have a Xeon system that is plenty powerful for my (C++) dev work, but I'm thinking of replacing it with an AMD build as it'll probably be cheaper over time. Then again, this is at Dutch energy costs, I'd imagine at (say) Texas cost it'd be different.