I installed SetCPU on my SK4G today, and for the most part things are running fine and I haven't had any problems.
At first I was getting a lot of lag and my phone kept freezing, so I checked this post and it helped me out a lot.
But I ran into one more problem. My phone keeps shutting off and I have to take out the battery and put it back in order to turn it on again. It's happened twice.
Could SetCPU be the cause of the problem?
Main / 816max - 312min (ondemand)
Temp > 35.6 C / 608max - 216min (ondemand / priority: 100)
Charging / 760max - 456min (ondemand / priority: 75)
Screen Off / 456max - 312min (ondemand / priority: 50)
I should also mention that I don't have a custom ROM or Kernel on my phone. It's just rooted.