You have to take in considerations a couple of things :
- How big is the room ?
- How close are those APs ?
- What type of wall structure in between rooms ?
- What's the Maximum/Min EIRP set to ?
- Are the AP wall mounted or ceiling mounted ?
But I think you should start by looking at the overall RF health before you move into looking at everything else .
When you get a chance run the commands I shared earlier, those could give a good idea .
Then if you don't find any issues there try updating the drivers of one of your laptop and see if it improves, you should also consider dropping multicast/broadcast.