If changing the graphic settings works, you could do one of the following to minimize the impact on the system:

1. enable the high performances only for Sweet Home 3D as described here;
2. if you're running on a laptop you can set high performances only when the pc is plugged.[/list=a]
   The first option is the recommended one. If the first option doesn't work and you cannot reboot the pc when high performance is enabled, the second option give you a chance to reboot the pc by simply unplugging the power.
   
   Anyway, before doing any of the above, ensure your graphic drivers and motherboard drivers are up to date.