GFIs do not trip due to overcurrent, they trip due to faults.
If plugging one of your powerstrips in causes a trip, it's because you have a fault someplace. What I'd do is unplug everything from both strips. Then plug the two strips in, and start plugging one item in at a time until you find the one that's causing the trip. You'll likely find that one item is doing it, regardless of how many other things are (or aren't) plugged in. That piece of equipment has a ground fault and should be repaired or replaced.
One exception is electronic ballasts. Sometimes electronic ballasts can generate harmonics that confuse the circuitry inside the GFI and cause what's known as 'nuiscance tripping.' Narrow it down as I described above and post your results.