It is a hit or miss, for me SU 10 was the best in terms of performance, never had the same performance as pre Xbox but good enough.
There are many tutorials on what setting causes CPU vs GPU workload on YouTube, that has been great help for me.
But the latest SU runs very poorly on my machine, for the first time since release over 2 years ago I have hit the uninstall button, I am tired of this yo-yo. Rolling dice with every update is becoming frustrating. There are winners and losers with each update, now it is my turn so I will give it a rest for 6 months.