Rebbe,
When the Gemara said that Rav Perayda taught his talmud a sugya 400 times each day until he got it. Was that a guzma or did he really teach it to him 400 times? If so wouldn't that have taken all day or most of the day? Would he have had time for anything else like other talmidim, his own learning or mitzvos like the dvar mitzvah that he wanted to leave in order to accomplish?
B'kavod,
Sam Kosofsky
I had the same problem as you.
Yet if the four hundred is a Guzma, then why did he live four hundred years as a reward (or was that also a Guzma!). And besides, Tosfos would probably have remarked that it is a Guzma had it been one (as they usually do). See also Agados Maharsha, who explains the number four hundred, an indication that he understood it literally.
The only suggestion I have is that the Kadmonim were blessed with a far greater capacity than we have and were able to achieve far more in less time.
be'Virchas Kol Tuv
Eliezer Chrysler