Setup guide

Chapter 4: Configuring Your Pro Tools System 43
 Lower CPU Usage Limit settings limit the ef-
fect of Pro Tools processing on other CPU-inten-
sive tasks, such as screen redraws, and are useful
when you are experiencing slow system re-
sponse, or when running other applications at
the same time as Pro Tools.
 Higher CPU Usage Limit settings allocate
more processing power to Pro Tools, and are use-
ful for playing back large sessions or using more
real-time plug-ins.
The maximum available CPU Usage Limit de-
pends on the number of processors in your com-
puter and on the number of processors you spec-
ify for RTAS processing. This value can range
from 85 percent for single-processor computers
to 99 percent for multi-processor computers.
On multiprocessor computers, the maximum
CPU Usage Limit is reduced when you use all
your processors (as selected in the RTAS Process-
ing pop-up menu). For example, on dual-proces-
sors, the limit will be 90%. On four-processor
computers, the limit will be 95%.
To change the CPU Usage Limit:
1 Choose Setup > Playback Engine.
2 From the CPU Usage Limit pop-up menu, se-
lect the percentage of CPU processing you want
to allocate to Pro Tools.
3 Click OK.
RTAS Engine (RTAS Error Suppression)
The RTAS Engine option determines RTAS error
reporting during playback and recording. This is
especially useful when working with instrument
plug-ins.
You should only enable RTAS error suppression
if you are experiencing frequent RTAS errors
that are interrupting your creative workflow.
When RTAS error suppression is enabled, you
can experience a degradation of audio quality.
However, this may be acceptable in order to
avoid interrupting playback and recording
when working with instrument plug-ins. Be sure
to disable RTAS error suppression when you
need to ensure the highest possible audio qual-
ity, such as for a final mix.
To enable RTAS error suppression:
1 Choose Setup > Playback Engine.
2 Select Ignore Errors During Playback/Record.
3 Click OK.
RTAS Error Suppression Option
On Pro Tools|HD systems, there is a single RTAS
Engine option:
Ignore Errors During Playback/Record When en-
abled, Pro Tools continues to play and record
even if the RTAS processing requirements ex-
ceed the selected CPU Usage Limit. This can re-
sult in pops and clicks in the audio, but does not
stop the transport.
Increasing the CPU Usage Limit may slow
down screen responses on slower computers.