Memrise flashcard system has added a “Speed review” feature.
One can speed review words, then only do the “classic” slow review of those words you might not remember. This should speed up reviewing words one has already learned.
I can spend as much as a minute on each flashcard, so 5 second answers is MUCH faster than I usually proceed. At 5 seconds, I barely have a chance to run my eyes over the 4 choices, and have to go on gut reactions rather than memory associations and process of elimination.