UNFILTER uses some very complex mathematics, and thus uses a considerable amount of CPU processing time. Here are a couple of suggestions how you can get the most out of your CPU:

• Try increasing buffer sizes in your host software to their largest values, then gradually bring them back down until you find a suitable balance between latency and CPU load. In Logic Pro, this also includes the "Process Buffer range" parameter. We recommend using an I/O buffer size of at least 1024 samples.
• Try closing the GUI of any plug-in that you don't currently need to have visual feedback on, including UNFILTER after adjusting settings.
• Quit any open applications that are not needed.
• In Logic Pro, all processes that are fed by a live source are processed on one CPU core. Bounce/record any live inputs feeding into UNFILTER to allow Logic to assign cores as needed. "Live" inputs include Instrument tracks that are record enabled.
• In Pro Tools, using a multi-mono instance is preferable to using a stereo instance in terms of CPU consumption, as this allows Pro Tools to render the channels on separate cores.
• In Pro Tools 10, render to a new file by pasting the setting used in a real-time instance into the AudioSuite version of UNFILTER for processing. The RTAS plug-in does not support AudioSuite.
• In general, when using multi-channel versions of the plug-in, please bypass any channels that you don't really need to process (like the LFE channel, for example).