Performance becomes a real concern when CSV files contain thousands of contacts. Many lightweight or online tools struggle at this point. However, WholeClear CSV to VCF Converter is designed for bulk CSV to vCard conversion and handles large files smoothly. Since it works offline, system resources are used more efficiently and there’s no dependency on internet speed. From what I’ve seen, the software processes large CSV files without freezing or crashing, even during long conversions. This makes it suitable for business users or anyone migrating large address books. As long as the system meets basic requirements, the conversion remains stable and predictable, which is exactly what users expect in bulk contact processing.