iMac slow

Thanks for the report. The reason your iMac is very slow is due to the 5400 rpm hard drive. Very slow. If you use an external SSD and run macOS from that, it will make your Mac 10 to 80 times faster for storage, depending on what external SSD you buy. For more info, instructions, and what external SSD to buy, please read: How to Setup and Use an External SSD as y… - Apple Community.

Cheers,

Jack

Welcome to the Apple Support Communities.

I believe we need to proceed with an EtreCheck report. EtreCheck is a useful App to diagnose and identify issues, both hardware and software. It is trusted by many users. Please follow the steps outlined below:

1. Navigate to: https://etrecheck.com and get the free version of EtreCheckPro.
2. Download it. It is a free and trusted app. It is often recommended here on Apple Support Communities. 
3. Open EtreCheck, and before running the report, be sure to check “Allow full Drive Access” at the bottom of the EtreCheckPro window.
4. Run the report, and put it in a post, as seen here: https://discussions.apple.com/docs/DOC-250000211. We will then examine the report for issues in your Mac.

Cheers,

Jack

I got a Report from EtreCheckPro as you suggested.

EtreCheckPro version: 6.5.1 (6F003)

Report generated: 2021-08-10 15:16:27

Download EtreCheckPro from https://etrecheck.com

Runtime: 7:18

Performance: Below Average

Problem: Computer is too slow

Major Issues:

    Anything that appears on this list needs immediate attention. 

    Kernel panics - This system has experienced kernel panics. This could be a sign of hardware failure.

Minor Issues:

    These issues do not need immediate attention but they may indicate future problems or opportunities for improvement. 

    Low performance - EtreCheck report took an unusually long time to run.

    Heavy I/O usage - Your system is under heavy I/O use. This will reduce your performance.

    x86-only Apps - This computer has x86-only apps might not work on future versions of the operating system.

    Kernel extensions present - This computer has kernel extensions that may not work in the future.

Hardware Information:

    iMac (Retina 4K, 21.5-inch, 2017)

    iMac Model: iMac18,2

    3 GHz Quad-Core Intel Core i5 (i5-7400) CPU: 4-core

    8 GB RAM - Upgradeable by an Apple Authorized Service Provider

        BANK 0/DIMM0 - 4 GB DDR4 SO-DIMM 2400 

        BANK 1/DIMM0 - 4 GB DDR4 SO-DIMM 2400 

Video Information:

    Radeon Pro 555 - VRAM: 2 GB

        iMac (built-in) 4096 x 2304

Drives:

    disk0 - APPLE HDD HTS541010A9E632 1.00 TB (Mechanical - 5400 RPM)

    Internal SATA 3 Gigabit Serial ATA

        disk0s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

        disk0s2 [APFS Container] 1000.00 GB

            disk1 [APFS Virtual drive] 1000.00 GB (Shared by 6 volumes)

                disk1s1 - Macintosh HD - Data (APFS) [APFS Virtual drive] (Shared - 229.75 GB used)

                disk1s2 - Preboot (APFS) [APFS Preboot] (Shared - 546 MB used)

                disk1s3 - Recovery (APFS) [Recovery] (Shared - 626 MB used)

                disk1s4 - VM (APFS) [APFS VM] (Shared - 5.37 GB used)

                disk1s5 (APFS) [APFS Container] (Shared - 15.33 GB used)

                    disk1s5s1 - Macintosh HD (APFS) [APFS Snapshot] (Shared - 15.33 GB used)

                disk1s6 - Update (APFS) (Shared - 3 MB used)

    disk2 - WD Elements 2621 2.00 TB

    External USB 5 Gbit/s USB

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

        disk2s2 - WD (Journaled HFS+) 2.00 TB (1.13 TB used)

Mounted Volumes:

    disk1s1 - Macintosh HD - Data [APFS Virtual drive]

        1000.00 GB (Shared - 229.75 GB used, 766.04 GB available, 748.16 GB free)

        APFS

        Mount point: /System/Volumes/Data

    disk1s2 - Preboot [APFS Preboot]

        1000.00 GB (Shared - 546 MB used, 748.16 GB free)

        APFS

        Mount point: /System/Volumes/Preboot

    disk1s4 - VM [APFS VM]

        1000.00 GB (Shared - 5.37 GB used, 748.16 GB free)

        APFS

        Mount point: /System/Volumes/VM

    disk1s5s1 - Macintosh HD [APFS Snapshot]

        1000.00 GB (Shared - 15.33 GB used, 766.04 GB available, 748.16 GB free)

        APFS

        Mount point: /

        Read-only: Yes

    disk1s6 - Update

        1000.00 GB (Shared - 3 MB used, 748.16 GB free)

        APFS

        Mount point: /System/Volumes/Update

    disk2s2 - WD

        2.00 TB (1.13 TB used, 865.32 GB available, 865.30 GB free)

        Journaled HFS+

        Mount point: /Volumes/WD

Network:

    Interface en0: Ethernet

    Interface en1: Wi-Fi

        802.11 a/b/g/n/ac

    Interface en4: Bluetooth PAN

    Interface bridge0: Thunderbolt Bridge

    iCloud Quota: 1.77 TB available

System Software:

    macOS Big Sur 11.5.1 (20G80) 

    Time since boot: About 4 hours

Security:

    Gatekeeper: App Store and identified developers

    System Integrity Protection: Enabled

    Antivirus software: Apple

Old Applications:

    20 x86-only apps

Kernel Extensions:

    /Applications/Wondershare Filmora9.app

        [Not Loaded] SystemAudioRecorder.kext - com.Perfect.Driver.SystemAudioRecorder (Wondershare Software Co., Ltd, 1.1.0 - SDK 10.9)

System Launch Daemons:

    [Not Loaded] 36 Apple tasks

    [Loaded] 188 Apple tasks

    [Running] 138 Apple tasks

    [Other] 2 Apple tasks

System Launch Agents:

    [Not Loaded] 17 Apple tasks

    [Loaded] 170 Apple tasks

    [Running] 145 Apple tasks

    [Other] 2 Apple tasks

Launch Daemons:

    [Loaded] com.adobe.ARMDC.Communicator.plist (Adobe Systems, Inc. - installed 2021-01-08)

    [Loaded] com.adobe.ARMDC.SMJobBlessHelper.plist (Adobe Systems, Inc. - installed 2021-01-08)

    [Loaded] com.microsoft.teams.TeamsUpdaterDaemon.plist (Microsoft Corporation - installed 2020-07-28)

Launch Agents:

    [Other] com.adobe.ARMDCHelper.cc24aef4a1b90ed56a725c38014c95072f92651fb65e1bf9c8e43c37a23d420d.plist (Adobe Systems, Inc. - installed 2021-02-11)

User Login Items:

    [Not Loaded] KakaoTalkHelper (App Store - installed 2021-08-05)

        Modern Login Item

        /Applications/KakaoTalk.app/Contents/Library/LoginItems/KakaoTalkHelper.app

Internet Plug-ins:

    AdobePDFViewer: 20.013.20074 (Adobe Systems, Inc. - installed 2020-12-07)

    AdobePDFViewerNPAPI: 17.012.20098 (Adobe Systems, Inc. - installed 2020-12-07)

Safari Extensions:

    Grammarly for Safari (App Store - installed 2021-07-27)

Backup:

    Auto backup: Yes

    Destinations: 

        WD [Local] (Last used)

            Total size: 2.00 TB

            Total number of backups: 80

            Oldest backup: 2019-09-25 17:56:01

            Last backup: 2021-08-10 13:55:16

    9 local snapshots

    Oldest local snapshot: 2021-08-09 16:06:48

    Last local snapshot: 2021-08-10 14:28:12

Performance:

    System Load: 1.22 (1 min ago) 1.33 (5 min ago) 1.26 (15 min ago)

    Nominal I/O speed: 35.97 MB/s

    File system: 43.67 seconds

    Write speed: 66 MB/s

    Read speed: 66 MB/s

CPU Usage Snapshot:

    Type Overall

    System: 5 %

    User: 9 %

    Idle: 85 %

Top Processes Snapshot by CPU:

    Process (count) CPU (Source - Location)

    system_profiler (2) 24.90 % (Apple)

    EtreCheckPro 14.34 % (Etresoft, Inc.)

    trustd (4) 6.62 % (Apple)

    com.apple.photos.VideoConversionService 5.58 % (Apple)

    WindowServer 4.50 % (Apple)

Top Processes Snapshot by Memory:

    Process (count) RAM usage (Source - Location)

    EtreCheckPro 599 MB (Etresoft, Inc.)

    system_profiler (2) 534 MB (Apple)

    com.apple.WebKit.WebContent (5) 500 MB (Apple)

    MTLCompilerService (24) 223 MB (Apple)

    backupd 166 MB (Apple)

Please post the full report according to https://discussions.apple.com/docs/DOC-250000211.

Jack

Thanks for your advising.