You can say either: 1. I found I was able to [or "could"] learn faster using this approach than I ever COULD while in university [You have to change "had" to "was able to" or "could" there because "learn faster" is understood as those verbs' complement, and that infinitive construction does not work with the auxiliary verb "had". Or you can say "I ever had learnt".] or 2. I have found I AM able to [or "can"] learn faster using this approach than I ever COULD while in university Which you use depends on the context. If it's all in the past, then the first form is more likely, but if it continues to have relevance in the present, then the perfect of the second is better. For example, the sentences might continue thus: 1. " ... so the next time I took a class, I made sure it followed that approach" 2. " ... so the next time I take a class, I'll make sure it follows that approach"

( I have found I was able to learn faster using this approach than I ever had while in university . ) NO because it is the PAST. ( I have found (out that) I am able to learn faster using this approach than I have ever had while in university . ) ( I found (out that) I was able to learn faster using this approach than I ever had while in university . ) ( I had found (out that) I was able to learn faster using this approach than I had ever had while in university . )

The difference between the sentences is the time in which the result was found. The first sentence use the 'simple past'. The second sentence uses the 'present perfect'.