>You mean that I do exactly the same query
Yes.

> and having set the prepared property to .t. will make it faster ?
To be honest, I don't think that prepared property will have any effect on performance.

Long time ago I played with some of those properties (but I was using remote views) and I didn't see any performance benefit. Some people that I talked to told me that they didn't any experince any performance benefit either. Of course, that was long time ago and I was using remote views. Perhaps SQL pass through will work a little bit different but I doubt it.

Let me know what your findings are.