M-AUDIO Pro Tools Recording Studio - Manual (Page 62)

Pro Tools Reference Guide 44
To set the number of RTAS Processors:
1 Choose Setup > Playback Engine.
2 From the RTAS Processing pop-up menu, select
the number of available processors you want to
allocate. The number of processors available var-
ies depending on how many processors are
available on your computer:
• Select 1 Processor to limit RTAS processing
to one CPU in the system.
• Choose 2 Processors to enable load balanc-
ing across two available processors.
• On systems running four or more proces-
sors, choose the number of processors for
RTAS processing.
3 Click OK.
System Usage Window and RTAS Processing
The System Usage window displays the com-
bined amount of RTAS processing occurring on
all enabled processors with a single indicator, re-
gardless of how many processors are available in
the system. If the System Usage Window shows
that you are at the limit of available resources,
increase the number of RTAS processors and ad-
just the CPU Usage Limit setting. (For more infor-
mation, see “System Usage” on page 56.)
CPU Usage Limit
The CPU Usage Limit setting controls the per-
centage of CPU resources allocated to Pro Tools
host processing 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 effect
of Pro Tools processing on other CPU-inten-
sive tasks, such as screen redraws, and are use-
ful 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 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% for single-processor computers (ex-
cept for 003, 003 Rack+, 003 Rack, Digi 002, and
Digi 002 Rack, which have a limit of 99%), and
99% for multiprocessor computers (which dedi-
cate one entire processor to Pro Tools).
On multiprocessor computers, the maximum
CPU Usage Limit
is reduced when you use all your
processors (as selected in the RTAS 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.
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.
On Pro Tools|HD systems, there is a single RTAS
Engine
option. On Pro Tools LE systems, there
are two options.
Increasing the CPU Usage Limit may slow
down screen responses on slower computers.