Because today's workforce is highly mobile, small wireless devices are being used to support mobile work collaboration. However, do computer platform differences affect such collaborations? This question is investigated through a controlled experiment that examines collaborative problem solving on different combinations of small and large computers. Experiment participants in the study work together on solving 2- and 3-dimensional variations of the popular Tetris™ game. Gender is used as a moderating variable to ascertain if prior observed effects on groups of males would be found among females. The findings indicate that platform differences affect communication and social behavior among both groups. Unexpectedly, collaboration amongst partners using small handhelds was the most cooperative and friendly because of the difficulty of solving the problem with the small device.