The ARCHLine.XP Render engine does not use the graphics card (GPU).
Since CPU rendering usually takes a heavy load, the computer is barely usable due to "limited" computing power.
If your CPU usage is 100 percent at all times, you'll start setting issues with your system performance., and you'll notice that all of your apps will feel slower than usual.
It is recommended to limit the CPU usage under 80-90 percent while the render is running.
It helps to use applications that require less computer (e.g. e-mail, Internet browser, etc.)
While Render is running, Processor affinity can be set in Windows - Task Manager, that is, it can be specified which processor cores should not be used by render. It is recommended to disable only one core. This will make the rendering a bit slower, but this way you can use another application.