input causing 100 percent processor usage

hello

i amm writing application which input from RS232 serial port, and I notice that the input become garbaged if i move the mouse or write on keyboard or otherwise interact with system. setting priorityy higher using nice command partially helps the problem but this is no long-term solution.

i then noticed that if i do not have anything running at all(except the photon microGUI) and i move mouse, processor usage goes very high sometimes to 100%

i am using qnx momentics/neutrino 6.3 FULL commercial version from original qnx media. the computer is a standard atx style pc, pentium II. as this is a Real Time development box only qnx is installed, so i cannot test using windows or linux. i suspect possibly either qnx configured incorrectly or something is wrong with computer hardware itself.

thank you for any help you can

Umm, try turning off the the desktop backdrop picture.