Modern Excel is a resource hog. It connects to the cloud, checks for updates, and indexes files in the background. By contrast, the Excel 2003 Portable version is sipping resources. It can run comfortably on machines with as little as 64MB of RAM. In developing nations or industrial settings where hardware refresh cycles are measured in decades, the portable version breathes life into otherwise obsolete hardware.
File formats that are supported in Excel - Microsoft Support microsoft excel 2003 portable version exclusive