New iMac very slow to render large TIFF files

I did , just the same, either external on internal!

That's not a good sign. You may have a hardware issue with the iMac itself. In that regard, bad RAM would be the first thing I would suspect. But it could be anything to do with the logic board, or the onboard Radeon.

Try resetting the SMC:

Reset the SMC of your Mac - Apple Support

For a 2020 Intel based iMac, that should be the If you have a Mac with the Apple T2 chip section.

Etrecheck gives us a concise report with all the info in one place. Make sure to give it full disk access.

etresoft wrote:

A contributing factor is likely the differences in operating system versions. Apple tends to rewrite the Preview app every year. And every year, they get it wrong. I've already confirmed that Preview doesn't even handle colorspaces properly. That's really bad. So it wouldn't surprise me if there are other parts broken too.

Preview is probably relegated to the interns, or incompetent developers like me.

vasileios225 wrote:

Do I understand that the latest version of the PREVIEW might be less capable than the older one?

Preview definitely has a colorspace bug. Another recent version was unable to properly handle monochrome images. I wouldn't be able to definitively confirm my theory unless I had a file that could reproduce the problem. But still, 2 minutes is a very long time. For comparison, I have a 100 MB WebP-encoded TIFF file that only takes one minute to render on an iPhone 6S. Preview can't even open those files at all. I can't imagine your computer taking twice that long on a more conventional TIFF file.

So now I intend to Erase my iMac and Reset it to factory settings and then load JUST the TIFF file NOTHING ELSE and see what happens! This will be a test to determine what might be the problem. I will report back.

Please do follow up. You have a few 3rd party system extensions, some of them partially installed and/or failing. Make sure to try Preview again before you reinstall any 3rd party software.

And I should reiterate those unanswered questions from my previous post. Those answers really would be critically important to solving this problem.

vasileios225 wrote:

I would be more than happy to ‘download a similarly sized TIFF file from some public source’. Please guide me where on the Internet can I get it? I am here to solve my problem, and no I am not an expert!!

I found a couple of sample satellite images. Both of these files should open instantly in Preview.

Here is a 240 MB TIFF image: download link via eatlas.org.au

Here is a 544 MB TIFF image: download link via earth.esa.int

These are the best links I could find. It seems like the last vestiges of the old internet have been swept away. All of the publicly accessible imagery from even a couple of years ago is gone. What's left is JPEG files or databases that require login and pretty deep knowledge to navigate.

That first file is a bit smaller than your problematic file, but it should be big enough. The second file is decent, but something is seriously wrong with that server. It took 17 minutes to download that file. It should have taken less than a minute.

It sounds like you've eliminated the possibility of a bad external drive. It also sounds like you've eliminated the possibility of any hardware problems since your 3rd party apps still work fine.

I recommend reviewing how you are generating this TIFF file. Whatever you're doing is not compatible with the current version of Apple's Preview. Given how much trouble I had locating a suitable file, it looks like Apple is right to drop support for unusual TIFF files. Since you have good 3rd party tools, continue to use those. But if you need to share these files with someone else, I recommend using JPEG or PNG.

vasileios225 wrote:

My take is hardware, maybe graphics card, but I can’t explain that some 3rd party Apps do work properly!

I think you're right. That's the only explanation. Your "new" Mac is still an Intel model. The graphics cards in the old Intel machines were notoriously bad. There is a reason why Apple dropped the whole Intel architecture.

My iMac is still covered by Apple Care, but I would imagine that I would have some hard time to convince them to replace the card, especially after they have declared the iMac as OK, passing all diagnostics successfully!

Take those two files with you. Put them on a USB stick. It won't take them 8 minutes to realize that it's not working.

It could be the graphics card in the sense that only when large images are opened, those higher registers of the VRAM come into play, but not for smaller images, or general rendering of the GUI.

We had a similar issue many years ago in a print shop I worked at. One particular Macs kept causing data lines in images saved back to the server. They weren't visible in Photoshop while the operator was working in the image, but the next time that file was opened, then you saw the corruption.

It took a while to first narrow it down to which of the eight Mac stations the problem was stemming from. And then more time to figure out it was only when working on large images corruption occurred. Once we knew that, we replaced one of the 16 GB sticks of RAM, and the problem was gone.

But it is more certainly looking like a hardware issue. Could be the graphics hardware, could be something else on the logic board. But either way, Apple should look the iMac over to figure it out.

Well this beats me, really frustrating!!

That's certainly understandable. There's no logic for the slow access from the same drive.

1. What brand of drive is it?
2. How does it connect? Directly to the newer Mac, or through a hub?
3. Is it an SSD or hard drive?
4. What is the format of the external? HFS+? APFS?

When you first acquired the external drive, did you erase and reformat it? There's often hidden junk on them that interferes with the OS.

Delete these files & restart...

~/Library/LaunchAgents/com.srib.pssddaemon.plist

~/Library/LaunchAgents/com.samsung.portablessd.mon.plist

~ tilde indicates your home folder

Apple hid the Users' Library folders...

Method 1:

1 From the Finder, select the Go menu at top of the screen, and choose Go to Folder.

2 In the window that opens, enter ~/Library, and click Go.

Or…

Use the Command-Shift-period

System modifications - There are a large number of system modifications running in the background.

I have no idea which ones you can get rid of, but that would help.

Seems the crashing started on 10/08, about the time of the OS updat.

If still not working...

Start with this of M1 or M2 Mac...

On your Mac, choose Apple menu  > Shut Down.

Wait for your Mac to shut down completely. A Mac is completely shut down when the screen is black and any lights (including in the Touch Bar) are off.

Press and hold the power button on your Mac until “Loading startup options” appears.

Select a volume.

Press and hold the Shift key, then click Continue in Safe Mode.

The computer restarts automatically. When the login window appears, you should see “Safe Boot” in the menu bar.

Restart normally.

If still not working...

Manually Rebuilding Spotlight via Terminal

If the aforementioned Spotlight control panel approach doesn’t spur a reindexation of the drive, you may need to initiate it manually through the command line. Open Terminal and use the following command string to do so:

sudo mdutil -E /

This basically asks for temporary super user status, which is why Terminal may ask you for your password (it may not if you’ve used a sudo command recently or are already logged in as a super user or root. The command asks the unix tool mdutil to reindex the spotlight database for everything on the computer, including external drives, mounted disk images, etc. To re-index only for a specific drive, use the /Volumes path. For example, for an external drive named “MiniMe,” the command would look like this:

sudo mdutil -i on /

Rebuilding a drive index can take a long time, so be prepared to wait whether you do it through the System Preference panel or the command line.

If still need be…

Open Terminal and run each of these one at a time

/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -domain local -domain system -domain user

sudo will ask you for an Admin password that won't be echoed.

Carefully type your admin password when asked & hit enter.

sudo /System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -seed -lint -r -f -v -dump -domain local -domain system -domain user -domain network

killall Dock

sudo mdutil -E /

sudo mdutil -i on /

Rebuilding a drive index can take a long time, so be prepared to wait whether you do it through the System Preference panel or the command line.

If still not working reinstall the OS.

vasileios225 wrote:

Yes same file on both computers, old one renders almost instantaneously, new one takes about 2 minutes!! (500MB TIFF PHOTO of mine. So frustrating. Etrcheck didn’t reveal any major problem!

Where is the file? I noticed that you had an external drive connected. Is the file only on the external? If so, what happens when you copy the file to the local hard drive?

If the file is already on the local hard drive, then the computer is dead. 2 minutes for a 500 MB TIFF isn't slow. It's dead. The slowest Intel computer I have available is a 2014 MacBook Pro. It can download a 500 MB TIFF file from iCloud Drive and then open it in 15 seconds. Just opening it is instantaneous.

And you are opening this file using only Preview, correct? It's not that there's anything wrong with other apps, it's just that those can't be independently tested and compared by other people.

You said this issue is long standing. What does that mean? You've had trouble with this specific file for some time? How long? You've had trouble with all files? Which files? How long? Were they all on this same external drive?

Important note - I've asked a lot of questions in this post. Please answer them all. They are all important.

Just curious where people are finding 500MB TIFF files? A full screen screen shot of my 24" iMac (4480x2520) saved as an uncompressed TIFF is only 33.3MB. A 13440x7560 uncompressed TIFF is only 305MB.