In my online rpg we have a chat system, so you can type messages to one another. It seems that, on lower framerates, sub30 fps, you will type something and some of the keys aren't registered at all. For instance, you will type "Hello, how are you?" and you KNOW you hit all the keys, and in the chat window you see "Hel howae yu".
I did further testing to make sure it wasn't just my python code, and sure enough, the problem is traced right back to the sensors.
In the test blend, wait until the framerate is below about 20 fps, and then press the d keya few times, watching the debug prop "press". Every once in a while, you will press the key and the number won't rise. I have been running tests of 50 presses, and depending on framerate get different results. I get somewhere between 40-45 presses out of 50 tries if the framerate is between 20 and 30; about 35 at 15 fps, and if the framerate is really low, hardly any keypresses ever count.
Not sure if this is a fixable problem or not, but blender definately seems to have more of a problem with keypresses than other applications. In a word processing program for instance, if my computer is running really slow, I can usually type out a whole word and it just takes a lot longer for what I type to show up. But it remains accurate to what keys I actually pressed.
I have tried to bypass the problem by using pygame to detect keypresses, but as that has to have its own window to detect keys its not a very workable solution.