Inconsistent app launch times in macOS

[snyp1193]

I posted this on Reddit but I figured I’d ask here too.

I have a refurbished iMac 2019 i5/512GB SSD/24GB RAM and majority of the time apps would launch in 1-2 bounces. However I’ve noticed all of a sudden they take longer to launch (like after 3-6 bounces). This occurs on apps that have not been launched since a fresh boot and it happens randomly and then after a few hours or sometimes few days it seems to go back to “normal”.

I’ve tried clean installs of macOS Catalina and reset PRAM/NVRAM several times but I can’t figure out what’s causing it. I thought maybe it’s an app/process issue and booted into safe mode but I see this behaviour there too. Is there some sort of weird caching that’s going on which makes it faster/slower? I don’t know if this is a macOS, SSD, or processor issue. iStat menus show SSD health at 100%.

Just wondering if anyone encountered this behaviour on their macs too?

 

[honestone33]

Have not noticed this issue, but a couple of things to consider:

1. Make sure you are using the latest version of the app.

2. Have as much free space as possible on the SSD.

What version of Catalina are you using? I am on the latest one, OS 10.15.7.

 

[snyp1193]

Have not noticed this issue, but a couple of things to consider:

1. Make sure you are using the latest version of the app.

2. Have as much free space as possible on the SSD.

What version of Catalina are you using? I am on the latest one, OS 10.15.7.

I’m on 10.15.7, everything is up to date. I see this behaviour on every app I have installed like Spotify, Facebook Messenger, Discord, Pages/Keynote/Numbers, etc. I’m currently at about 50% space but I’ve had this problem on 75%-85% free space too. It’s so weird and annoying.

 

[brianmowrey]

Already made sure no firmware password so P/NVRAM actually works?

Even if an app has been cycled out of RAM Cached, most will open semi-instantly on a SSD. So, if P/NVRAM reset doesn't fix, it's time for OS reinstall

 

[snyp1193]

Already made sure no firmware password so P/NVRAM actually works?

Even if an app has been cycled out of RAM Cached, most will open semi-instantly on a SSD. So, if P/NVRAM reset doesn't fix, it's time for OS reinstall

No firmware password and I’ve done the reset and multiple OS reinstalls over the past few months. It’s also not something that I want to drag my 27” iMac to the Genius Bar for as I can’t reproduce it at any given moment. Like I said it happens randomly.

 

[brianmowrey]

No firmware password and I’ve done the reset and multiple OS reinstalls over the past few months. It’s also not something that I want to drag my 27” iMac to the Genius Bar for as I can’t reproduce it at any given moment. Like I said it happens randomly.

Oof... Well, myself, I’ve evolved into regular Nvram resets (on account of booting into my HDD on High Sierra to play old 32b games on Steam on the reg), as well as shutdowns every day, because I place high stock in how consistently fast my SSD boots and opens apps under this regime. Even if I am investing more time than I am saving.

For your machine, if the slow app openings are recurring under a less obsessive shut-down/reset-NVRAM regime, it might not be a sign of anything other than your use of one-too-many poorly optimized non-core apps “gumming up the works”

 

[snyp1193]

Oof... Well, myself, I’ve evolved into regular Nvram resets (on account of booting into my HDD on High Sierra to play old 32b games on Steam on the reg), as well as shutdowns every day, because I place high stock in how consistently fast my SSD boots and opens apps under this regime. Even if I am investing more time than I am saving.

For your machine, if the slow app openings are recurring under a less obsessive shut-down/reset-NVRAM regime, it might not be a sign of anything other than your use of one-too-many poorly optimized non-core apps “gumming up the works”

I’m hoping to do a clean install again when Big Sur comes out and then only install apps that I really need and monitor the behaviour and then slowly re-add apps to see if the problem re-occurs. I’ve hesitated bringing this up because it’s very difficult to explain, but it’s noticeable when you use your Mac day to day and observe this behaviour.

 

[AppleSmack]

Slow by design:

Michael Tsai - Blog - macOS 10.15: Slow by Design

Tldr: slow because it's checking _*everything*_ with Apple's servers - security over performance

 

[brianmowrey]

Slow by design:

Michael Tsai - Blog - macOS 10.15: Slow by Design

Tldr: slow because it's checking _*everything*_ with Apple's servers - security over performance

That's not impossible. But the trustd blip in Network activity should be almost instantaneous. One could test just by using another Mac with Catalina on the same network. But I'm on telmex DSL, where iCloud IMAP only connects once a week, but opening any random third party app from launchpad is instantaneous.

Any delays after the first time an app is opened, if they are related to security, would more suggest conflicts in local TCC land, i.e. conflicting files or references or messed up file permissions, not a trustd ping which should take a nanosecond.

 

[honestone33]

I’m on 10.15.7, everything is up to date. I see this behaviour on every app I have installed like Spotify, Facebook Messenger, Discord, Pages/Keynote/Numbers, etc. I’m currently at about 50% space but I’ve had this problem on 75%-85% free space too. It’s so weird and annoying.

I’m hoping to do a clean install again when Big Sur comes out and then only install apps that I really need and monitor the behaviour and then slowly re-add apps to see if the problem re-occurs. I’ve hesitated bringing this up because it’s very difficult to explain, but it’s noticeable when you use your Mac day to day and observe this behaviour.

Sorry to hear you are experiencing this problem, especially when it is so, so difficult to pin down. I myself am kind of a "simple minded" user, in that for about 99% of my computer usage, I only run one app at a time. And typically none of them need much memory and/or resources. You certainly have done all the right things: clean installation of Catalina, using the latest versions of software, and having plenty of free space on your internal SSD. Possibly another contributing factor could be the brand of SSD inside your iMac. But given that it is a 2019 model, I doubt the read/write speeds of your 512 gig SSD would be slow.

 

[snyp1193]

Sorry to hear you are experiencing this problem, especially when it is so, so difficult to pin down. I myself am kind of a "simple minded" user, in that for about 99% of my computer usage, I only run one app at a time. And typically none of them need much memory and/or resources. You certainly have done all the right things: clean installation of Catalina, using the latest versions of software, and having plenty of free space on your internal SSD. Possibly another contributing factor could be the brand of SSD inside your iMac. But given that it is a 2019 model, I doubt the read/write speeds of your 512 gig SSD would be slow.

Yeah it’s still puzzling. Although I’ve done a Blackmagic speed test recently and I’ve noticed my read speeds fluctuate occasionally by 300-400 mbps. 1900mbps instead of 2300-2400mbps which is the average for the 2019 iMac 500GB SSD. I don’t know if that’s a sign of something and I don’t think Apple will replace it since it’s already still quite fast.

 

[AAPLGeek]

Yeah it’s still puzzling. Although I’ve done a Blackmagic speed test recently and I’ve noticed my read speeds fluctuate occasionally by 300-400 mbps. 1900mbps instead of 2300-2400mbps which is the average for the 2019 iMac 500GB SSD. I don’t know if that’s a sign of something and I don’t think Apple will replace it since it’s already still quite fast.

Blackmagic speedtest only measures sequential read and write speeds which are largely pointless unless all you’re doing is moving large files around.

Real world usage like app launching requires hundreds of random IO operations which is where random read/write speeds and drive latency come into play.

You can get AmorphousDiskMark app from the Mac App Store and check your drive for random IO performance issues.

Also get the DriveDx app to rule out any drive degradation or health issues.

 

[snyp1193]

Blackmagic speedtest only measures sequential read and write speeds which are largely pointless unless all you’re doing is moving large files around.

Real world usage like app launching requires hundreds of random IO operations which is where random read/write speeds and drive latency come into play.

You can get AmorphousDiskMark app from the Mac App Store and check your drive for random IO performance issues.

Also get the DriveDx app to rule out any drive degradation or health issues.

Thanks I’ll give AmorphousDiskMark a try. I used DriveDx before and it shows perfect health, 100% everything. However it has about 14TB of writes (possibly cause I got mine refurbished).

 

[tyc0746]

Do you have any background apps running, such as anti-virus, cataloging utilities, system scanners?

 

[snyp1193]

Do you have any background apps running, such as anti-virus, cataloging utilities, system scanners?

Not that I’m aware of. I did a macOS reinstall multiple times with different apps installed each time and they all have the same behaviour. Apps start launching faster and then slower between reboots and it’s not even consecutive reboots. Sometimes the slowdown lasts few hours between reboots or 1-2 days between reboots. It’s very random.

The behaviour seems almost like there is a “cache” of the apps which makes it load faster and the OS cleans itself randomly and takes a while for it to re-cache, thus in the meantime it becomes slow. It just doesn’t make sense since if it’s between reboots it would not be cached on the ram. Unless there’s some caching that macOS does on the SSD? I've never experienced this on any macOS version in the past.

Here is an video example I took 2 days ago on a fresh boot:

Here is a video example I took today on a fresh boot:

Nothing was installed/updated in the meantime. It may not seem significant for these apps but some "poorly optimized apps" like MS Word will take 5-6 bounces instead of 2-3. This behaviour will happen on and off.

Any one experience something like this?

 

[tyc0746]

I assume the more resource-hungry the application, then the more bounces as it has to load a lot more data just to get up & running.

I have different number of initial bounces for different apps, and a much older machine

For example...first launch of the day (from an overnight shut-down):

1. AppleTV (1 bounce, but takes a couple of seconds for anything to actually show up in the 'Watch Now' window)
2. iMazing (3 bounces)
3. FF-Works (2 bounces)
4. MS Excel 365 (3 bounces)
5. MS Word 365 (3 bounces)
6. MS Powerpoint 365 (3 bounces)
7. MS Outlook 365 (3 bounces)
8. Adobe Acrobat DC 2020 (1 bounce)
9. Adobe Illustrator 2021 (7 bounces)
10. Adobe Photoshop 2021 (9 bounces)
11. Adobe InDesign 2021 (9 bounces)

Second/subsequent launches of the day:

1. AppleTV (0 bounces)
2. iMazing (1 bounce)
3. FF-Works (1 bounce)
4. MS Excel 365 (1 bounces)
5. MS Word 365 (1 bounce)
6. MS Powerpoint 365 (1 bounce)
7. MS Outlook 365 (1 bounce)
8. Adobe Acrobat DC 2020 (0 bounces)
9. Adobe Illustrator 2021 (2-3 bounces)
10. Adobe Photoshop 2021 (3-4 bounces)
11. Adobe InDesign 2021 (3-4 bounces)

We know there is some caching for frequently-used apps, and the system will always be slowest first thing, and straight after a reinstall (due to all the background initialisation stuff MacOS is doing) and first launch of a new app will be slower due to the notarisation checks the OS will run.

I'll download some of those apps you've got installed and see what mine does...

1) First launch after downloading (includes all the initial checks and prompts to allow notifications, accessibility, etc.)

2) second launch after downloading & installing

3) first launch after boot

4) second launch after boot

 

[brianmowrey]

The behaviour seems almost like there is a “cache” of the apps which makes it load faster and the OS cleans itself randomly and takes a while for it to re-cache, thus in the meantime it becomes slow. It just doesn’t make sense since if it’s between reboots it would not be cached on the ram. Unless there’s some caching that macOS does on the SSD? I've never experienced this on any macOS version in the past.

Catalina and APFS Mojave use some of the boot disk for virtual memory. You can see how large that volume is in diskutil list. Then, there's a certain core of "cached files" in RAM that are loaded either during bootup or the second you log in, plus a few more that trickle in once login items get going. Then there's what's there after you open apps. You can switch from your main User to a second User with just Activity Monitor open and observe that the other User has access to the same cached files (it is higher than it would be if you had not logged in your main and opened some apps first). On a machine with 24GB there shouldn't be a lot that "leaves" cached files while you are still powered on. And even then, there shouldn't be a "looking for" previously cached files that causes slower openings than after boot.

Conversely, on a machine with 8GB or less (or 16GB with really heavy use), that is the moment where things would slow to a crawl as OS X would have to clear some cached files from other apps, plus compress currently running apps, to make room for the currently reopening app.

Which brings up the question, are you hitting high green or more on memory pressure in Activity Monitor during your daily use?

 

[snyp1193]

I assume the more resource-hungry the application, then the more bounces as it has to load a lot more data just to get up & running.

I have different number of initial bounces for different apps, and a much older machine

View attachment 995708

For example...first launch of the day (from an overnight shut-down):

1. AppleTV (1 bounce, but takes a couple of seconds for anything to actually show up in the 'Watch Now' window)
2. iMazing (3 bounces)
3. FF-Works (2 bounces)
4. MS Excel 365 (3 bounces)
5. MS Word 365 (3 bounces)
6. MS Powerpoint 365 (3 bounces)
7. MS Outlook 365 (3 bounces)
8. Adobe Acrobat DC 2020 (1 bounce)
9. Adobe Illustrator 2021 (7 bounces)
10. Adobe Photoshop 2021 (9 bounces)
11. Adobe InDesign 2021 (9 bounces)

Second/subsequent launches of the day:

1. AppleTV (0 bounces)
2. iMazing (1 bounce)
3. FF-Works (1 bounce)
4. MS Excel 365 (1 bounces)
5. MS Word 365 (1 bounce)
6. MS Powerpoint 365 (1 bounce)
7. MS Outlook 365 (1 bounce)
8. Adobe Acrobat DC 2020 (0 bounces)
9. Adobe Illustrator 2021 (2-3 bounces)
10. Adobe Photoshop 2021 (3-4 bounces)
11. Adobe InDesign 2021 (3-4 bounces)

We know there is some caching for frequently-used apps, and the system will always be slowest first thing, and straight after a reinstall (due to all the background initialisation stuff MacOS is doing) and first launch of a new app will be slower due to the notarisation checks the OS will run.

I'll download some of those apps you've got installed and see what mine does...

1) First launch after downloading (includes all the initial checks and prompts to allow notifications, accessibility, etc.)

View attachment 995712​

2) second launch after downloading & installing

View attachment 995714​

3) first launch after boot

View attachment 995713​

4) second launch after boot

View attachment 995715​

When you mean “subsequent launches” was that in the same boot session or did you re-boot your Mac?

 

[snyp1193]

Catalina and APFS Mojave use some of the boot disk for virtual memory. You can see how large that volume is in diskutil list. Then, there's a certain core of "cached files" in RAM that are loaded either during bootup or the second you log in, plus a few more that trickle in once login items get going. Then there's what's there after you open apps. You can switch from your main User to a second User with just Activity Monitor open and observe that the other User has access to the same cached files (it is higher than it would be if you had not logged in your main and opened some apps first). On a machine with 24GB there shouldn't be a lot that "leaves" cached files while you are still powered on. And even then, there shouldn't be a "looking for" previously cached files that causes slower openings than after boot.

Conversely, on a machine with 8GB or less (or 16GB with really heavy use), that is the moment where things would slow to a crawl as OS X would have to clear some cached files from other apps, plus compress currently running apps, to make room for the currently reopening app.

Which brings up the question, are you hitting high green or more on memory pressure in Activity Monitor during your daily use?

Nope, I’m very far from the memory limit. It’s quite low throughout the day as I don’t actually use many RAM intensive apps. What’s strange is I also have a work MacBook Pro 16” with the same macOS 10.15.7 but app launches behave more consistently. Although that is using Firevault so apps generally take a bit longer to open anyways, but it’s consistent. This is very peculiar problem on my iMac.

I appreciate everyone here putting in their analysis! I guess I’ll just assume “this is how it is”.

 

[tyc0746]

When you mean “subsequent launches” was that in the same boot session or did you re-boot your Mac?

Within the same session (it boots at 8am and stays on until 11pm)...unless I have to reboot it for some other reason.

But I'm using each of those listed apps about twice an hour, so they don't get a big break between uses. Maybe they'd fall out of the cache and take more bounces to open if I didn't use them for 2/3/4 hours?

 

[snyp1193]

Within the same session (it boots at 8am and stays on until 11pm)...unless I have to reboot it for some other reason.

But I'm using each of those listed apps about twice an hour, so they don't get a big break between uses. Maybe they'd fall out of the cache and take more bounces to open if I didn't use them for 2/3/4 hours?

My problem is between reboots, not within the same session. They always re-launch fairly instantly in the same session (like yours) regardless of how long I haven't used the apps after closing them. It will behave slow after rebooting and then suddenly few reboots later (may it be hours or days later) it will get faster, just like I showed in the two clips. This keeps happening multiple times over an entire month.

 

[Feyl]

It's not relevant to your problem but I'd like to say something about the macOS performance in general. In short, it's not bad but it's not great. I have two computers at the moment, MacBook Air 2019 and a Windows PC that I built myself. The Windows machine has a fairly regular SATA SSD and it's performing very snappy in comparison with the Mac which has a superior SSD that it's at least two times faster. But I'm not seeing it anywhere. Safari takes 2-3 bounces to launch, file operations are not amazing and the boot time oh my god. The Windows machine boots in like 10 seconds and the Mac takes at least double. I observed that the longer boot times came with the transition to APFS in High Sierra. Apple should focus on this first rather than making questionable design changes.

Also, I don't game on my computers so they have the same integrated GPUs but again. Windows is amazingly smooth in every corner of the OS but macOS stutters here and there. And both machines runs on the same resolution. I strongly prefer my Mac but the truth is that Windows is much better in the performance department.

 

[snyp1193]

It's not relevant to your problem but I'd like to say something about the macOS performance in general. In short, it's not bad but it's not great. I have two computers at the moment, MacBook Air 2019 and a Windows PC that I built myself. The Windows machine has a fairly regular SATA SSD and it's performing very snappy in comparison with the Mac which has a superior SSD that it's at least two times faster. But I'm not seeing it anywhere. Safari takes 2-3 bounces to launch, file operations are not amazing and the boot time oh my god. The Windows machine boots in like 10 seconds and the Mac takes at least double. I observed that the longer boot times came with the transition to APFS in High Sierra. Apple should focus on this first rather than making questionable design changes.

Also, I don't game on my computers so they have the same integrated GPUs but again. Windows is amazingly smooth in every corner of the OS but macOS stutters here and there. And both machines runs on the same resolution. I strongly prefer my Mac but the truth is that Windows is much better in the performance department.

Yeah I’ve noticed macOS performance degraded over the past decade while Windows improved significantly. You could run macOS faster than Windows on a HDD but now an NVME SSD on macOS performance slower than SATA SSD on Windows. I don’t know why their optimization is so poor for macOS compared to iOS.

 

[snyp1193]

App launches seem to feel more consistent with a fresh install of Big Sur so far. Will test over the next few days/weeks to see if I have this issue again.