Slow fetch to data grid in 12.8

Hi,

This is in my newly installed Toad 12.8.0.49 (64 bit), under Win7 Pro.

When I execute a query (ctrl+Enter) I immediately get “Row 1 of 500 fetched so far”.
I also get one green square in the bottom, right corner and after some 8-9 seconds the result is show in the data grid.
It doesn’t matter if I change the query to give just a single row back, the actual fetch still takes way too long (8-9 secs).
After the fetch I get some “42 msecs” in the lower left…

Running the same query in my old Toad (11.6.0.43) using the same connection, the result is shown at once (both single row and thousands of rows).
Both Toad versions use the same sql*net client, Instant Client 11.2.0.3.

Is there some setting that could cause these slow fetches in 12.8?

Kind regards

Tomas