60 fps does not work when the tm1637 screens are on

I have dashboard with rgb leds gear matrix and 2 tm1637 screens. When i turn off the tm1637 screens dashboard works great in 60 fps. When i turn on the screens, fps drops, I don't know how much, but it's very noticeable, maybe down to 20+- (simhub still shows 60 at this time). Why so and what can be done about it? I clearly remember that a few years ago in previous versions of simhub I had 60 fps even with the displays turned on, so I think the problem is in the program.