Welcome to the forums!
You have two options at this point:
1. You can find and install an operating system that works well on your hardware
or
2. You can try to troubleshoot the Ubuntu problem.
Either way you will get good support on these forums.
My recommendation is to start with #2. If you are having a performance problem with Ubuntu, tools exist to help troubleshoot. You're already off to a good start by telling us about your hardware. The next step is to tell us exactly what you mean by "hideously slow to stop" because honestly I have no idea what that means.