If the raw data you are processing is larger than your onboard RAM, processing will slow dramatically.
An easy check is to open the Task Manager and look for 100% memory usage while SlantView is processing. Once the RAM is full, the computer relies on "virtual memory", meaning it uses empty space on your hard drive as additional RAM.
To ensure this does not happen, we recommend having twice the amount of RAM as the largest dataset you plan to process. Keep in mind operating systems, antivirus software, and other open applications can take up a large percentage of your computer's available RAM.