The UNICODE provider string keyword

If the UNICODE provider string keyword is set to FALSE (default), the code page corresponding to the CLIENT_LOCALE must be present as one of the operating system code pages. In this situation, the OLE DB Provider uses functions to convert from DB_LOCALE to CLIENT_LOCALE, then uses operating system functions to convert from CLIENT_LOCALE to Unicode. This mechanism does not load the code page, which results in better connection performance but slower code set conversions.

If the UNICODE provider string keyword is set to TRUE, the code page corresponding to the CLIENT_LOCALE does not need to be present as one of the operating system code pages. In this situation, the OLE DB Provider uses functions to convert directly from DB_LOCALE to Unicode. This mechanism loads the code page, which might slow connection performance slightly but results in faster code set conversions.