Your code runs fine here. From my accumulated zen wisdom in how this stuff goes down, whenever there seems to be odd issues where the very same code runs differently on other machines, it usually is some hardware difference.... maybe the io from the /dev/dsp is better from the /dev/dsp on some machines, and on others, the oss io is flawed and creates a bottleneck. Who knows? But the code you posted is valid, runs here fine, and what else can I say except check those differences in the kernel and software updates from Ubuntu 10.04 to 10.10, and see how they may affect your particular hardware. You don't even mention if the 2 machines have the same hardware... ie processor speed, ram, and soundcard.