Virtualisation is a prevalent technology in current computing. Among the many aspects of virtualisation, it can be employed to reduce hardware costs by server consolidation, implement "green computing" by reducing power consumption and as an underpinning process for cloud computing enabling the creation of a range of virtual networks and virtual supercomputers. This paper presents performance measurements for a cloning system known as iVIC that has been developed in Beihang University, China. In an extension to earlier work, it focuses on the factors the limit the number of clones that can be successfully started. IVIC creates clusters of virtual computers that can communicate with each other through virtual switch mechanisms. The virtual switches can also allow communication between the clone environment and the physical world. Testing has been undertaken to identify the limiting factors for creating and starting numbers of clone machines, measure the power consumption of the physical system and the computational performance capability of the clones.