I have had this issue for a long time, and I started a thread about it and called a long time ago. It will work normally sometimes so it is hard to reproduce at every given moment. I have a personal built computer with the following specs:
i7 860 processor
8GB RAM
Samsung SSD (Windows 8.1/Logos/programs)
3 SATA drives
850 Watt Power Supply
GTX 570 2+ GB RAM (2 LG 23" monitors)
GTX 560 2 GB RAM (2 ASUS 21" monitors)
Those are my current specs, but the same issues have occurred with a SATA HDD as my main drive, different video cards and only one monitor on the secondary, and under Windows 7 and 8. I think it also happened under L4.
The problem is tha tin the main Logos window, there appears to be some sort of refresh issue when all monitors are in use. For instance, I have a main window open with after a homepage passage guide search for John 20, and then I opened my bibles in a floating windows, and I also opened two additional commentaries. My main windows with the commentaries is painfully slow when scrolling. I can scroll, and it may take many seconds for it to actually move, but if I right click on the page it seems to force a refresh. The floated window works without issue. Just a minute ago, I had both windows minimized, and when I maximized them the floated window worked normally, but the main windows was just black. I clicked in on it, and it appeared slowly in parts, as though it could not refresh the entire picture at once.
If I go into resolution and turn off all but one monitor, everything works normally. It will also work for a short time after I reinstate the other three monitors, but it will eventually slow down again. I have been dealing with this for a long time now, and I have never seen anyone else bring this issue up, but I can't be the only one!