Reading and writing the same 500,000 rows x 14 columns in different formats on a Mac M1 Air using Easy Data Transform v1.43.0:
| Format | Read (seconds) | Write (seconds) |
|---|---|---|
| Tab Separated Value (unquoted) | 1.203 | 0.516 |
| Comma Separated Value (quoted) | 1.980 | 0.870 |
| Excel XLSX | 30.314 | 31.302 |
So tab separated without quoting is the best choice for performance, as long as your data doesn’t contain tabs. And Excel is much slower than either comma or tab delimited.