> When having performance problems, how do you determine if it's > because there is not > enough RAM or the CPU cannot keep up? The only way in which the amount of RAM has an impact on your performance, is when your system has to swap too often. If you notice that simple things start to take a long time and are accompanied by a lot of disk access, this might indicate that you could do with more RAM. Performance problems related to the CPU maxing out are more gradual and consistent; the cpu load in the performance meter will go up with the amount of plugins you use and once it reaches the top you'll get regular overload messages. > In the System Performance meter window, why are there 2 columns for > audio? and exactly > what is it measuring. The "audio" really indicates how much (or really how little) free time is left for the CPU (which does all the audio calculations). In your case, there are two CPU's so two meters. The more idle cycles performed by the CPU, the lower the meter indication. > Exactly what is the Disk I/0 meter measuring. It measures how much (or really how little) free time is left for harddisk communication. If you play back 64 tracks on a slow harddisk, your CPU might have lots of time to spear but an overload will be caused by the fact that the data can't be read from disk quickly enough. Since swapping happens through the same harddisk interface, a lack of memory could also increase disk i/o. > Anyone know where, in the main Reference manual the System > Performance window is > explained? I found by accident using the key command Option-X. I don't have the manual at hand but I'm sure it's in there. :o) Maurits.