The truth of the matter is just like that. There are time when thought does not help.
This was an idea I heard from someone who was getting married in Israel and he had spent a few years going through the entire Shas every month. [That is the whole Gemara. That is a little more than 100 pages every day].
He said not to even think if you are understanding your learning or not. This to many people may sound ridiculous but in fact it contains a deep insight. There are times when thought does not help.
I found this to be the case in yeshiva. I would go through a small section of gemara--just saying the words. Then the Rashi on that Gemara. At that point I understood nothing. But then after a few more readings of the same gemara I would get the idea. Thus I got the idea that even when I think I am not understanding, something is being absorbed.
There are other areas of learning that I find it better just to read the material straight with no review until I have finished the entire book. That is, just to say the words and go on. Math and Physics I find to be more amenable to that kind of learning.
I should mention that Reb Freifeld of Yeshivat Shar Yashuv held by review. That is specifically 10 times. Whether it was a chapter of Gemara or Tosphot, his main thing was to do review. I never got past this problem that I needed to make progress and yet the Rosh Yeshiva was emphasizing review. I still have no idea how to deal with this problem except to mention that in the Mir it was the accepted path to do in depth learning in the morning and to make progress in the afternoon. That does not really answer the question but at least it is a kind of middle path.
[I must mention also that without Rav Freifeld's emphasis on in depth learning I am sure I would not be able to learn. To "know how to learn" is something I have seen that people need to get when they are young or they never get it. But it should be said that very few people understood what Rav Freifeld was doing. I felt very frustrated on his emphasis on learning in depth and I am sure a lot of other people felt the same way. Only later I realized the fact that when people do not get this right away in their first years in yeshiva, they never get it.
In the Mir yeshiva the whole question became mute,- because anyway the morning was for in depth learning and the afternoon for fast learning. That more or less answered the whole issue simply.