We are using FOP and the transform() function of javax.xml.transform.Transformer to render tiff image from inputted XML and XSL-FO. Execution of transform() function is causing CPU to reach at 100% utilization during image rendering. So during continuous Image rendering requests, the CPU usage remains around 100% that stopped other applications to continue their work on that system. We also tried the same using FOP command line but get similar results. In fop.xconf we are using following settings: 1. tiff image compression type as CCITT T.6 2. DPI as 200dpi. 3. default-page-settings as height="3.625in" and width="8.5in"/> This problem is not specific to particular XML and XSL-FO. We are looking for a fix in FOP so that CPU utilization can be reduced during execution of transform() function. Do let me know in case other information is required.