Specifications

Pro Tools Reference Guide68
CPU Usage Limit
The CPU Usage Limit setting in the Playback En-
gine controls the percentage of CPU resources al-
located to Pro Tools host processing tasks. Used in
combination with the
Host 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
effect of Pro Tools processing on other CPU-in-
tensive tasks, such as screen redraws, and are
useful when you are experiencing slow system
response, 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
RTAS plug-ins.
The maximum available
CPU Usage Limit depends
on the number of processors in your computer and
on the number of processors you specify for host
processing. This value can range from 85% for sin-
gle-processor computers (except for 003,
003 Rack+, 003 Rack, Digi 002, and Digi 002
Rack, which have a limit of 99%), and 99% for
multiprocessor computers (which dedicate one en-
tire processor to Pro Tools).
On multiprocessor computers, the maximum
CPU
Usage Limit
is reduced when you use all your pro-
cessors (as selected in the
Host Processing pop-up
menu). For example, on dual-processors, the limit
is 90%. On four-processor computers, the limit is
95%.
To change the CPU Usage Limit:
1 Choose Setup > Playback Engine.
2 From the CPU Usage Limit pop-up menu, select
the percentage of CPU processing you want to
allocate to Pro Tools.
3 Click OK.
Host Engine (Error Suppression)
The Host Engine options in the Playback Engine
determine error reporting during playback and re-
cording. This is especially useful when working
with instrument plug-ins.
On Avid HDX and Pro Tools|HD systems, there is
a single
Host Engine option. On host-based
Pro Tools systems, there are two
Host Engine
options.
• Enable error suppression only if you are experi-
encing frequent errors that are interrupting your
creative workflow. When error suppression is
enabled, you can experience a degradation of au-
dio quality. However, this may be acceptable in
order to avoid interrupting playback and record-
ing when working with instrument plug-ins.
• Disable error suppression when you need to en-
sure the highest possible audio quality, such as
for a final mix.
To enable error suppression:
1 Choose Setup > Playback Engine.
2 Select Ignore Errors During Playback/Record.
3 If available, you can also select Minimize
Additional I/O Latency
.
4 Click OK.
Increasing the CPU Usage Limit may slow
down screen responses on slower computers.