If you receive an out of memory message while opening a large PostGIS table, then you must enable the Use Declare/Fetch setting in the PostgreSQL Unicode driver's connection properties.
You can locate your ODBC drivers in the Windows Control Panel in Administrative Tools. Select ODBC Data Sources (64-bit) to open the ODBC Data Source Administrator. On the User DSN tab, double-click the PostgreSQL Unicode driver from the list. The PostgreSQL Unicode ODBC Driver Setup dialog box opens. Click Datasource to open the Advanced Options dialog box and select the Use Declare/Fetch check box.