Is SQL developer installed on the same server with your QlikView Server/ Publisher? Otherwise, it's not a fair comparison.
First possibility is network issue - SQL developer might be in a server with a closer/ better network connection to Oracle than your QlikView server.
Also, if you query a large dataset, SQL developer only returns part of the data for preview. Meanwhile, in an ODBC connection, the whole data must be downloaded, which may explain the difference.
You can try to install Excel on your QlikView server, and try loading data from the same ODBC driver (instruction at Connect to an ODBC source - Excel). This will help you identify whether the issue is on QlikView or the driver side
There is only 1 second of data in the DocumentLog, and there is no error. You will need to increase the verbosity for the Distribution tasks. When you run that script with QlikView Desktop, how long does it take and how does the script log look like (e.g.: which table or step is the more time consuming)?
When you say connecting to Excel is giving out of memory, when does exactly that error appear? Because it is very rare unless there is an error in the script or app itself (or maybe even a bug). Does it happen also with QlikView Desktop?