The minimum recommendation for Mac users is OS 10.3 or higher , a G4 1 GHz processor and 512 MB of RAM.

Here are 9 hints to improve Marratech's performance on your computer

System tray applications can often be terminated by right-clicking them and choosing Exit or Quit.

On Windows 2000 and XP, the Windows Task Manager is useful for monitoring the CPU load. Open it with <shift> + <ctrl> + <Esc>. Choose the Processes tab and sort the processes by CPU load. TaskInfo2000 is a useful shareware application that works under Windows 98. On Mac, you may use the Process Viewer (Under Applications, Utilities)

2. Upgrade your operating system and drivers
By upgrading to your manufacturer's latest drivers and operating system patches, you will often notice increased speed and stability. Running Windows Update (On Windows) or System Update (on Mac) frequently is recommended.

3. Your processor speed settings
Be sure your processor is at maximum speed. Newer computers may have a battery save mode or power conservation mode that reduces your system's performance.

4. Use H.261 instead of H.264 Sending H.264 video in a meeting is more demanding than receiving from other participants so users running on slower computers can choose to send H.261 video instead. Change this under Tools/Preferences --> Video --> Compression.
5. Limit your Participants Refresh rate Using the Low Update Rate option for the Participants module saves processor power.
6. Limit Capture Frame Rate The frame rate for the video capture can also be limited to lower the CPU load. This will save a lot of CPU on slower Macs.
7. Disable the Lip-Synch option The Lip-Synch functionality can also be disabled to save CPU resources.
8. Disable resizable video window (Expert Mode only) Another video-related feature that can cause higher CPU load is the Resizable Window function (Tools, Options, Video).
Some machines' performance may suffer when the Resizable Window option is active. Deselect this to save on CPU power. The Lip-Synch functionality can also raise the CPU load to some extent..
9. Disable Use Scaling The Use Scaling function for scaling your video image on the Mac may use up your computer resources. Be sure to use this option with care.

Opening several Private Windows (Expert mode only) with video in them can also cause high CPU loads.

If the hints and tips above doesn't help, the most likely cause is a driver related problem. Check and if necessary update the audio and graphics cards drivers, as well as the drivers for video grabber cards and USB cameras.