whichi is faster using CreateOleObject or using connection to write xls file in delphi

It depends on the specific use case and the size of the data being written. In general, using a connection to write an XLS file is faster than using CreateOleObject. However, if the data being written is small, the difference in speed may not be noticeable. It's important to test both methods and choose the one that performs best for your specific scenario.