A computer system supports hosting of virtual desktops using resources available in the cloud. Instrumentation code is executed on a processor that minimizes the distortion to the processor resources used to execute the program to be profiled. In many embodiments, the compositions further include a carrier, e. Spreading digital image noise out in frequency allows a noise specification to be met without having to increase the frequency of the PLL reference clock. The system also controls the camera zoom to achieve a reference object presentation ratio during view following.