I had the Monster amp as I stated before in this thread and thought the same as you that the displays were not working. In reality the power needed for to run efficient speakers in a average size room is much less then I think most people realize. I was running mine with the outlaw 970 and I had to turn mine up to -5 or so to get 10 to 15 watts to appear on the meters. This was with music cds and it was deafing in my 10x15 room. I could not get the meters to show even 1 watt while watching SW Episode 3 until it was so loud I would have sworn I was in the battle. The reason that the displays flicker with higher out put is because these tend to be dynamic moments that require lots of watts quickly which large amps like the monster or the outlaws have in reserve. These peaks last for only an instant so that is why the the numbers seem to flicker due to the fact that the amp is outputing this power for only a split second. I would imagine that your amps and the 5990 are working just fine.