Studies have shown that for a significant fraction of the time desktop PCs and workstations are under-utilized. To exploit these idle resources, various Desktop/Workstation Grid systems have been developed. The ultimate goal of such systems is to maximize efficiency of resource usage while maintaining low obtrusiveness to machine owners. To this end, we created a new fine-grain cycle stealing approach and conducted a performance comparison study against the traditional coarse-grain cycle stealing. We developed a prototype of fine-grain cycle stealing, the Linger-Longer system, on a Linux cluster. The experiments on a cluster of desktop Linux PCs with benchmark applications show that, overall, finegrain cycle stealing can improve efficiency of idle cycle usage by increasing the guest job throughput by 50% to 70%, while limiting obtrusiveness with no more than 3% of host job slowdown.