You are running out of CPU power. Remove some RTAS plug-ins, or increase the CPU Usage Limit in the Playback Engine dialog. (-9128)

23 Dec 2008

Pro Tools

I've noticed a lot of people visiting this site looking for the answer to this question, so I'm going to try and expand on it a little further.

According to my understanding of the Pro Tools 101 Official Courseware, Pro Tools divides CPU power into groups, allocating cycles mainly to two groups: audio processing, and running the host software, or in laymen's terms: rendering a user interface, which is what we use to control Pro Tools in the first place. The user interface can be quite CPU intensive, especially with much to be redrawn, so if possible, it's always a good idea to ensure that there is as little as possible happening on screen.

The main setting you will be adjusting in order to find more CPU power will be from the Setup Menu, under Playback Engine. The dialogue contained within this window is scarce at best, and hardly describes at all the options mean, however the Pro Tools 101 documentation does. So what exactly does it mean?

1. Lower CPU Usage Limit settings limit the effect of Pro Tools processing on other processing-intensive tasks, such as screen redraws, and are useful when you are experiencing slow system response or when you are running other application at the same time as Pro Tools

2. Higher CPU Usage Limit settings allocate more processing power to Pro Tools and are useful for playing back large sessions or using more RTAS plug-ins

On paper, it looks as though you should just reef your settings up to the maximum, and away you go (as per the second point), but from much testing and experience, I have actually found that *lowering* the CPU setting yields better results (as per the first point listed above)! Both statements are somewhat ambiguous, and have obviously promoted some confusion amongst the community, however my experience is as such:

I am running very large sessions with multiple plug-ins on OS X 10.5.5 powered by an Intel 2.6 GHz Core 2 Duo with 4 GB 667 MHz DDR2 SDRAM and I don't have CPU issues. So what is my CPU setting at within Pro Tools?

Yep, just 85%! Try it, you may find it helps!