Oh in that case that's my bad; I thought I was being told I was using an outdated version and got confused!
If the performance issue is a known problem and the fixes are only in testing at the moment then I'm happy to endure a bit of extra CPU usage until they're released. I might see if I can find time to setup a VM to help test as I currently I have a spare disk that should have enough freespace to test against with the same huge writes I was doing before.