When solving problems there are two phases:
- Trial and error.
To let your unconscious chessmodule release stored patterns it is necesarry to trigger that. The release is triggered by a conscious effort. Scanning the board and making moves in your mind is such conscious effort. In the mean time is this conscious trial and error itself highly dependant from unconscious processes. What makes that you look conscious at Bc4 and forget to look at Bb5? The difference is caused by the unconscious processes that lie beneath.
Thoughtprocesses start out conscious, but soon they are transferred to the unconscious zone and steer from there the conscious trial and error. In the mean time does this trial and error not make a very effective impression.
Is there any need to extend the phase of trial and error to 30 minutes or more for a problem? Does the extra effort for those 30 minutes trigger the emotions that burn the pattern deeper in the brain? Or can you go immediately to the solution in order to make yourself familiar with the new pattern? During the trial and error phase, you don't really calculate. You are merely looking for clues and familiar patterns. When you conduct a game, this trial and error plays a lesser role since you most of the time have an idea what you want to head for. But when you look at a position that doesn't stem from one of your own games, it is more difficult to find a clue.
You can only start to calculate when all major motifs in the position are released by your chessmodule. As said, calculation doesn't seem to be the biggest problem.