Improving performance on a 2020 iMac 5k 27 in.

For an EGPU please begin with Use an external graphics processor with your Mac - Apple Support

Other than that there is not much you can do. However you should ensure none of the following types of third party apps are installed as a.they are 100% worthless b. Negatively affect performance c. Can damage Mac OS.

• Antivirus
• Cleaning
• VPN
• Security
• Maintenance

That model shouldn't be slow unless the storage system is failing or the computer is loaded with useless third-party fear-ware. Evaluating slowness is hard in a text-based venue like this where we can neither see nor touch your computer, but there is an effective way.

If you want a data-driven evaluation in this setting where we can neither see nor touch your computer, please post an EtreCheck report. We can quickly and within the limitations of these forums help you determine what issues are at play without our playing a protracted game of "20 Questions" with you that could go on for days. 

EtreCheck Pro is available here:

https://etrecheck.com/index

The free version will do nicely for this purpose, although the app is worthy of our financial support.

We can see hard data about drive performance, software issues and interferences, and RAM usage. Etrecheck is the development of a long-serving and trusted ASC contributor. It is a reporting app, not a "fix-it” app, expressly for displaying information in these forums to help us help you remotely. It will not reveal any personal or secure information.

Posting is important because the senior contributors here have reviewed thousands of EtreCheck reports and can often spot something that a new user may miss. Use the "Additional text" tool to post long reports like Etrecheck's:

E-GPUs just plug into an available port. There is no major hook up required. Once connected, the Mac should just detect it and you just need to set the relevant app to use it.

With that said, I would start by analyzing the Mac before going for extra hardware. It's likely something else is causing the lag, and adding external hardware is unlikely to improve it any.

I second Allan Jones suggestion of running an Etrecheck report and posting it here so we may peruse it and offer suggestions.

Also as rkauffman suggests, uninstall any antivirus, cleaning apps, malware scanners etc...

Perfect! Thank you.

Storage is the usual suspect in slow iMac reports, your factory Apple SSD is running a tiny bit under nominals but nowhere near enough to cause ] a noticeable slowdown in normal use. My 1TB SSD does about 2200-2700 (2017 iMac 5K) but your speeds are still faster than any non-SSD options in that model.

Remove CCleaner. Cat-like, Macs clean themselves with elegant automated self-maintenance routines that do ALL housekeeping required, even defragging, and without outside help. This has been a feature of macOS since 2000 and, to me, industry knowledge of the self-maintaining nature of macOS makes a scam of any third-party product that claims to clean and polish your Mac.

The other issue is the early versions of CCleaner were so badly ported from Windows that they were deleting important Mac system files a, leaving the computer unusable.

Try disconnecting the two USB 2 external drives:

disk2 - LaCie Mobile Drive 5.00 TB

External USB Up to 480 Mb/s USB 👈🏻

disk2s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk2s2 - L*****1 5.00 TB (481.90 GB used)

disk3 - LaCie Mobile Drive 5.00 TB

External USB Up to 480 Mb/s USB 👈🏻

disk3s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk3s2 - L*****2 5.00 TB (70 MB used)

It's a long shot but I have seen before-and-after EtreCheck reports here where a bus-powered USB2 drive slowed modern Macs, and disconnecting it restored performance. Easy enough to test.

Go ahead and restart the computer to freshen things up. It's been 10 days since last restart.

No it CCleaner.app is still installed. IF you cannot completely uninstall it then you need to download and use FindAnyFile and have it search for the CCleaner.app and anything with CCleaner name in it and fully Trash the app.

In addition I strongly suspect you have some pretty outdated apps installed including Wacome which is a know offender. All of your third party apps need to be up-to-date in order to get the best performance out of them and the Mac. All you need to do is to identify the third party apps installed by looking in the Apps folder then research the process to update them. Some may be automatic however some may not be so you need to dig deeper to see if the app itself has a utility built into the app to check and update if needed. If they do NOT have that then you need to research with the developer themselves.

Well, some CCleaner components are still there:

/Applications/CCleaner.app/Contents/Frameworks/com.piriform.ccleaner.update.bundle/Contents/XPCServices/com.piriform.ccleaner.update.xpc/Contents/Resources/launch.plist

Executable: /Applications/CCleaner.app/Contents/Frameworks/com.piriform.ccleaner.update.bundle/Contents/XPCServices/com.piriform.ccleaner.update.xpc/Contents/MacOS/com.piriform.ccleaner.update.xpc

You may have to visit the Piriform web site to get full removal instructions.

Does your DaVinci work involve those old USB 2 external drives? If they are used for a swap disk or the like, they can slow the process to a crawl. USB 3 is 10X faster the USB2. Thunderbolt 3 external SSD drives are compatible with your iMac and can be as fast as your internal SD.

If you are rendering from and back out to the slow external drives, that's going to be a major slowdown.

The issues is likely to be the adapter. The drives themselves are likely capable of faster transfer speeds but the adapter or hub probably is not.

I'd probably move the card reader from the USB-C port it's using to one of the USB-A ports and plug the drives directly into the USB-C port instead. The SD card reader does not need the extra speed.

You can even get a good USB-C / Thunderbolt dock for them so you can use both on the same port.

Start by removing CCleaner.

Also, your external drives are pretty slow. If you are rendering the video out to one of them, it's likely one of the major bottlenecks.