When your 5x5 stalls, hit up 3x3 with the weight you failed at then then continue to progress in your next workouts. Do that until you stall out then try a max test. After that, reset to a lighter weight to higher volume again. This works. I don't think its optimal but i've done it.

If your goal is just to increase your max lift then I would say try a ME/DE approach.

IronWorker