This article provides useful instructions on how to optimize Mac OS X for digital audio workstations. The first part is focusing on general operating system maintenance. More specific trouble shooting tips can be found in the second part which is dealing with CPU and performance related issues.

1. General Mac OS X Maintenance

1.1 Repairing Permissions

Beginning with OS X El Capitan (10.11), file permissions are automatically protected. The following instructions on reparing permissions are necessary and possible in older Mac OS X versions including Yosemite (10.10) only.

This is a classic Mac OS X trouble shooting issue. You'll get very different advices when it comes to the Repair Permissions function of the Disk Utility in Mac OS X. Some people recommend to repair permissions on a regular basis, some do this even before and after every single installation. Others never repair permissions without running into problems. At least it is important to know that there is the possibility of repairing permissions in case you are experiencing troubles with your system and/or Cubase:

• Go to Applications/Utilities and start Disk Utility.
• On the left side of the Disk Utility window select your system volume/partition.
• On the right side make sure the First Aid tab is selected and then click on the Repair Disk Permissions button. (Of course you may click on Verify Disk Permissons at first. But as most of the time there are some permissions that need to be repaired you can save some time by skipping the verification and starting the repair at once.)

Apple articles dealing with permissions:

About Disk Utility's Repair Disk Permissions feature
Troubleshooting permissions issues in Mac OS X

1.2 Running Maintenance Scripts

Mac OS X is a pretty carefree operating system. However, since some built-in maintenance scripts are scheduled to be executed in the middle of the night, some manual operation is necessary from time to time when your Mac is asleep at night. In Apple's words: "Mac OS X performs background maintenance tasks at certain times if the computer is not in sleep mode. If your computer is shut down or in sleep at the designated times, the maintenance does not occur. In that case, you may want or need to run these manually."

Read more: Mac OS X: How to force background maintenance tasks

1.3 Updating Mac OS X

You don't have to be the first one to install and run a Mac OS X update that has just been released. But in general it is good to keep your system up to date. At least when you want to keep your applications and drivers up to date. If you are unsure if a specific Mac OS X or QuickTime update is recommendable simply do a search in our user forums. New OS updates are discussed there almost immediately after the release and you can assume that eventual problems will be reported very soon by less prudent resp. bolder users.

1.4 Optimizing Hard Disks

Before you think about optimizing your hard drive (because someone told you this is a very important thing to do) please read this Apple article:

About disk optimization with Mac OS X

2. Possible Causes of Unusually High CPU Load

The following information might be of help if the VST Performance Meter in one of our applications is showing an unusually high load or even drop-outs and peaks are visible and audible.

2.1 Latency/Buffer Setting

The "ASIO" part of the VST Performance Window (Devices menu) indicates how much resources are left to calculate the audio data and forward it to the audio driver in time. If the latency is very low (which is corresponding to a very small buffer size) time might be too short for proper signal processing. Depending on the system, the audio interface and the running project, it might make sense to increase the latency/buffer setting. Please refer to the manual of the corresponding audio interface for details.

Updating the audio driver might also improve the overall system performance and allow using latencies which weren't usable before. Generally, internal audio cards using the PCI or PCIe bus are able to provide lower latencies than external USB or Firewire based audio interfaces.

2.2 Processor Perfomance Setting

On some Macs it is possible to adjust the processor's performance in order to save battery power. Open the Energy Saver panel (Apple menu > System Preferences...) in order to make sure that your Mac is calculating at full throttle... If available on your system, you'll find the corresponding settings under Options/Optimization.

Also note that MacBooks and MacBooks Pro do reduce processor speed if the battery is not inserted in order to prevent a an overload of the A/C adaptor.

2.3 Multi/Multicore Processors

Multiple cores and/or processors need system resources to synchronize the cores. This can also lead to peaks, drop-outs and a generally higher basic load. For details, please refer to this article.

2.4 VST Bridge

The VST Bridge enables old PowerPC (G4/G5 processors) based plug-ins to run on Intel-based Macs. Please note that certain "VST bridged" plug-ins create high processor loads and can cause performance issues. In general, it is recommended to use current plug-in versions that run natively on Intel-based Macs, if available. Check the plug-in manufacturer's site for update if you experience performance troubles with a PowerPC plug-in. For further details, please refer to this article.

2.5 Apple Airport

Apple Airport (WLAN) can cause performance issues when running challenging realtime applications. Particularly when working on large projects with a high basic load, disabling Airport might tip the scales.