Specifications

Pro Tools M-Powered Getting Started22
CPU Usage Limit
The CPU Usage Limit controls the percentage of
CPU resources allocated to Pro Tools host pro-
cessing tasks. Used in combination with the
RTAS Processors setting, the CPU Usage Limit
setting lets you control the way Pro Tools tasks
are carried out by the system.
 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
useful 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
specify with the RTAS Processor setting. This
value can range from 85 percent for single-pro-
cessor computers to 99 percent for multi-proces-
sor computers.
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 options determine 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 If available, you can also select Minimize Addi-
tional I/O Latency.
4 Click OK.
RTAS Error Suppression Options
There are two RTAS Engine options:
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.
Minimize Additional I/O Latency When enabled,
any additional latency due to suppressing RTAS
errors during playback and record is minimized
to 128 samples. Suppressing RTAS errors re-
quires at least 128 samples of additional buffer-
ing on some systems. If this option is disabled,
Increasing the CPU Usage Limit may slow
down screen response on slower computers.