If you’re finding this article because you’re looking for solutions to CPU or Hardware Buffer Dialog notifications, or you’re here because you’ve been linked from the official Avid Pro Tools Facebook Support Forum, we’re going to preface this article by suggesting that you read through our compendium carefully, and take a look / listen to our YouTube video discussing Pro Tools stability tips.
It’s quite clear that working with Pro Tools successfully requires a deeper level of knowledge about computers as well as about the DAW. While many DAWs may make music production simpler – that was their goal: to make music making more accessible for the non-engineer – Pro Tools doesn’t pull any punches.
It’s a powerful and complex app and it requires the right system, with all of its ducks in a row, to work efficiently. This is why Pro Tools may often see CPU and Hardware Buffer notifications – it’s more likely than not that your system is up to the task, but some work in your OS/Computer is required to make sure Pro Tools is able to function properly.
For this reason – a lot of the advice that we’ll disseminate in this article is for computer centric than Pro Tools centric.
What does CPU / Hardware Buffer Notifications refer to?
If you’re using Pro Tools | First, Pro Tools (Standard), Pro Tools HD Native, or Pro Tools Ultimate but running on a standard computer (ie not connected to HDX cards), then you’re running what’s referred to as a NATIVE system – the CPU is responsible for (largely) all of the Pro Tools audio tasks. But the CPU is also responsible for running the computer as well at the same time.
When a CPU notification appears, it’s telling you that there isn’t enough CPU time available to run what Pro Tools needs / what you’re asking it to do.
When a Hardware Buffer notification appears, it’s essentially saying the same thing. The selectable Hardware Buffer size (measured in Samples) – found in Setup -> Playback Engine – allows the user to ‘ask’ the CPU for more processing power to be given to Pro Tools’ audio tasks. Higher buffer sizes grant more CPU power to Pro Tools (at the behest of input latency) and lower buffer sizes reduce the load on the CPU.
The traditional ‘hardware buffer technique’ dictates that we use lower buffer sizes for tracking/recording (for the best latency) and higher buffer sizes for mixing, where the power is made available to run all of the plugins.
We tend not to see H/W Buffer notifications in HDX systems, where the audio processing load is shouldered by the DSPs – the CPU is largely not required in HDX systems (with caveats).
The CPU overlord
If you think about what a Pro Tools Computer is doing, it’s easy to see how much the CPU is responsible for. Running the OS, all of the background apps and processes, any open apps, the network and the internet, the bluetooth, hard drives, USB busses…. And the more you have running or connected, the more the CPU has to deal with – and this is on top of the 70 tracks that you’re working with in Pro Tools.
CPU tech is as good as its ever been in 2021 – chips are fast and efficient, providing us with multiple cores and hyper threading protocol to split tasks between the various cores, but even the best chips can become taxed, especially when you begin running more and more in the background because you feel that your CPU set *should* be able to handle it.
Making a stable system
So this compendium collates all of the advice that had been given over the years to diagnose what is causing CPU and Hardware Buffer notifications to appear. The answer is rarely obvious at the outset – but if you follow this advice from the start, over time, you’ll be able to narrow down where persistent problems lie.
Even the most battle hardened of Pro Tools experts see CPU and Hardware buffer notifications at least once a day – even on the most stable of systems. The difference is that we can click through and carry on – and/or be able to investigate the problem is the error persists.
Pro Tools Answers EP6 – Making your Pro Tools System Stable.
In Episode 8, we spent just over and hour discussing each of the top 10 suggests for making your Pro Tools system stable. Each subject was discussed for an average of 6 mins. Everything below will be a synopsis of the tip – if you want to hear deeper thoughts and contexts, our video will give you a little more insight.
#1 Making sure you’re compatible.
In order for Pro Tools to run smoothly and efficiently, you’ll need to run the app on hardware and software that it is able to work harmoniously with. Avid maintain compatibility documents that confirm which hardware and OS configurations that they’ve tested Pro Tools with.
Operating Systems are updated with regularity now and it’s easy for software builds to fall behind latest OS revisions when changes in OS revisions can cause conflicts with current Pro Tools releases.
If you’re getting errors from the outset – or after an update – checking the OS compatibility charts will either confirm that the OS may or may not be an issue.
Furthermore, you’ll notice that Avid are able to test the majority of Apple’s MacBook, iMac and Mac Pro ranges – the limited variation in hardware configurations allows this to be possible. Where Windows / PC is concerned, the sheer variety of hardware configurations makes it harder to specifically test specific models.
So hardware itself can also cause Pro Tools to stutter. You’d really find this from the outset, though, although this is much less of an issue today than it used to be.
Andy, Dave and Anders discuss this in a bit more depth in Ep 8.
#2 Make sure your plugins are up to date.
When you update your OS, or update your Pro Tools version, it’s worth checking to see if your plugins have also been updated to address any changes in the software. It’s quite easy for ‘old’ plugins to cause sessions to slow down where a latest release causes.
Where sessions do slow down, or crash out, it can be time well spent loading your session up with all of the Plugins deactivated (holding SHIFT when clicking the session to open) and then reactivating them one by one to see which causes the app to crash.
Avid Link goes along way to addressing this problem, notifying you when plugin and software updates are available. For your 3rd party library, though – you have to go through it manually.
Dave, Andy and Anders go into a bit more depth in Ep 8.
#3 Making sure drivers are up to date
Similar to plugins – when new versions of software are released, changes can affect the efficiency of your hardware drivers which can have a knock on effect in how Pro Tools interacts with them. In Ep6, we concentrate more on Interface drivers and front end GUIs, which can cause all sorts of efficiency problems when ‘old’ versions can’t interact with the newer releases properly.
Regularly checking for driver updates will make sure that changes to major software releases are addressed.
#4 Removing System Shortcuts
This is more of a navigation thing rather than system stability, but it’s worth de-associating your Function keys from OS actions such as volume, brightness, etc to give you shortcut access to some of Pro Tools’ key actions.
#5 Use dedicated drives for Audio
It’s long been discussed that your audio tasks should be kept separate from your System drive. The constant accessing/reading of your hard drive during playback (more so than recording), alongside the system constantly needing access as well, means that the audio streaming isn’t as efficient as it could be – and only gets harder as you use more tracks.
Not to mention that your system drive can wear out quicker which may eventually crash your entire computer.
Separating your system drive from your audio means that streaming your audio assets will always be as efficient as it can be. This is also true for Samples – storing these on separate drives is standard practice for some. And if you’re working with video, it’s even more important to keep these on a separate drive.
Things do become harder in this respect for Laptops but thankfully it’s not as tricky as it used to be. Normal, internal, SATA hard drives tend to have a transfer speed of at least 5Gbps – USB-3/C connected drives also provide a similar connection speed and Thunderbolt drives are higher still.
USB drives have always been gimped a little because the USB speed is shared between all of the connected devices (similar with Thunderbolt although the bandwidth is so high that it’s largely a moot point) but it’s unlikely to be a major problem.
So separating your audio assets from your main computer tasks will increase the efficiency of your system.
Dave, Anders and Andy go into a bit more depth in Ep 8.
#6 Use the Disc Cache and set it as low as you can get away with.
When Pro Tools streams audio from the hard drive, it passes through a small amount of RAM buffer before you hear it. This is partly the reason for a small delay when you hit play.
Increasing the Disc Cache means that more of your RAM is made available to the point that you can cache the entire timeline into your RAM, and your session will play back from RAM. This takes load away from the drives in that the drives are not responsible for managing the playback stream.
This is a great feature if you’re recording at higher sample rates.
But bare in mind that the more RAM you assign to the disc cache, the less is available for the system. Thus using too high-a-disc cache can have a negative effect.
Having a healthy amount of RAM (16GB min… but really 32GB is the ideal) can help your system to speed up a tad.
#7 Turn off other applications
We’ve discussed earlier than your computer’s CPU is responsible for everything that your computer is doing. So it follows that if you have too many apps open, the CPU will be spreading itself too thinly to be able to run Pro Tools efficiently.
Furthermore – apps also have a presence in RAM.
So when you’re working in Pro Tools, turn off any other applications and background tasks that you don’t need to ensure that the power is available for Pro Tools when it wants it.
#8 Turn of network connections
Similar to turning off background tasks – disconnecting network connections that you don’t need will free up CPU resources.
If you’re using iLok Cloud, you’ll obviously need to maintain the internet so this is likely OK. If you’re using ethernet based surfaces or audio interfaces, these will obviously be OK as well. But everything else that’s not required to run your sessions should go.
#9 Turn off Time Machine
Again – similar to the previous points. Time Machine will be using system resources to manage the constant backup regime. Disconnecting the Time Machine drive will turn this off and free up any CPU time it was taking.
#10 Think before you delete preferences
This suggestion has almost turned into a joke around PTA HQ! ‘Trashing the prefs’ rarely a solution and will probably cause more of a headache than anything because the behaviour of your Pro Tools system – that you’ve probably spent a while curating – will revert back to factory default! Furthermore – it’s unlikely to fix anything. In fact, it’s often then we’ll see “trash the prefs” suggestions met with “didn’t work” replies in the threads.
So we suggest ignoring this largely!
#11 Check your PSU
Quite important if you’re working on a laptop – using a PSU that’s of a lower power rating than the recommended one for the unit can mean that the computer will suck more power than the PSU can handle. It’s been shown that using a 65w PSU instead of a 85w PSU on a MacBook Pro 15”, for example, can result in more CPU notifications than running on the 85w where the 85w PSU is the required unit.
#12 Check your battery
When your battery becomes low or worn, it may not be able to provide the power required to maintain the CPU cycles for CPU intensive work, such as Audio. Turning off background apps can help, but only for a short time.
#13 Enabling graphics switching
Allowing your computer to switch to a lower graphics mode while working on the battery will help with efficiency – and again with one that’s been well used! Switching to a lower graphics mode will mean that the CPU isn’t working as hard to maintain the highest quality graphics – although switching has rarely caused any noticeable graphic reduction!
#14 Clean out your fans
When your CPU (and/or GPU) gets hot, it slows down and can’t compute. Audio tasks are intensive and the fans will usually kick in to keep the CPU cool and thus working at a decent efficiency. But if the fans or the vents are clogged, the cooling isn’t as efficient and the efficiency of the system is compromised – often resulting in software crashes (where the CPU can’t cope), complete crashes, or just a CPU efficiency reduction which results in CPU notifications.
#15 The Last resort, but maybe not!
If you’ve done all of these things and you’re still getting crashes or inefficiencies – a last resort is to re-install your entire system.
This does actually make a lot of sense – and it’s something that each of the PTA do at least once every year. Re-installing just wipes out all of that additional ‘stuff’ that you pick up during the natural course of using your computer and the nature of computers, software and share resources can have one piece of software affecting others in unexplained ways.
How often have you installed something that causes an issue with something else?!
A full on wipe/reinstall resets the playing field and reinstalling everything from scratch will usually result in a harmonious system. You can check everything as you go and will likely affect your quality of life in other areas of your computing experience.
It can take a few days – we usually set aside a week to ensure that the shutdown isn’t going to affect anything.
#15 Committing Plugins / Freezing Tracks
Let’s also not forget that even in a stable system, you can reach the limits that your perfectly managed Pro Tools system can handle.
In which case, this is where we would start committing tracks such as MIDI instruments – where the instrument VSTs themselves can use a lot of resources – and tracks using power hungry plugins.
Freeze tracks is a good temporary solutions, but it does prevent some other actions. It could be best to simply bounce (commit) certain tracks – with plugins – to an audio file to reduce the CPU load.
Do you have any further suggestions to add to our compendium that might help other users? Feel free to suggest them to us and we’ll add them if we feel that they’re strong enough candidates for causing CPU problems.