My iMac 27 2012 with 3TB Fusion drive had poor performance

My iMac 27 2012 was having poor performance problem. It was having random freeze, sluggish performance and long boot up time. Sometime it won't be able to wake from sleep. Also beach balling frequently even when web surfing from page to page. I'm not sure if the fusion drive problem or macOS 10.13.6 as I notice this problem when updated to this version. Here's the EtreCheck report below. Would be grateful if any expert could give me some advise on this. Million thanks.

EtreCheck version: 5.0 (5008)

Report generated: 2018-09-28 13:03:13

Download EtreCheck from https://etrecheck.com

Runtime: 10:53

Performance: Poor

Sandbox: Enabled

Full drive access: Disabled

Problem: Beachballing

Description:

My iMac 27 2012 was having random freeze, sluggish performance, and long boot up time. Sometime it wont be able to wake from sleep. Also beach balling frequently even when web surfing.

Major Issues:

Anything that appears on this list needs immediate attention.

No Time Machine backup - Time Machine backup not found.

Poor performance - EtreCheck report took over 10 minutes to run. This is very unusual.

Minor Issues:

These issues do not need immediate attention but they may indicate future problems.

Unsigned files - There are unsigned software files installed. They appear to be legitimate but should be reviewed.

32-bit Apps - This machine has 32-bits apps that may have problems in the future.

Hardware Information:

iMac (27-inch, Late 2012)

iMac Model: iMac13,2

1 2.9 GHz Intel Core i5 (i5-3470S) CPU: 4-core

32 GB RAM - At maximum

BANK 0/DIMM0 - 8 GB DDR3 1600 ok

BANK 1/DIMM0 - 8 GB DDR3 1600 ok

BANK 0/DIMM1 - 8 GB DDR3 1600 ok

BANK 1/DIMM1 - 8 GB DDR3 1600 ok

Video Information:

NVIDIA GeForce GTX 660M - VRAM: 512 MB

iMac 2560 x 1440

Drives:

disk0 - APPLE SSD SM128E 121.33 GB (Solid State - TRIM: Yes)

Internal SATA 6 Gigabit Serial ATA

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

disk0s2 [Fusion Drive] 120.85 GB

disk2 - M****D (Journaled HFS+) 1.56 TB (190.47 GB used)

disk0s3 - B*******X 134 MB

disk1 - APPLE HDD ST3000DM001 3.00 TB (Mechanical - 7200 RPM)

Internal SATA 6 Gigabit Serial ATA

disk1s1 - EFI (MS-DOS FAT32) [EFI] 210 MB

disk1s2 [Fusion Drive] 1.44 TB

disk2 - M****D (Journaled HFS+) 1.56 TB (190.47 GB used)

disk1s3 - Recovery HD (Journaled HFS+) [Recovery] 650 MB (575 MB used)

disk1s4 - S********D (Journaled HFS+) 1.56 TB (182.57 GB used)

Mounted Volumes:

disk1s3 - Recovery HD [Recovery] 650 MB (75 MB free)

Journaled HFS+

Mount point: /Volumes/Recovery HD

disk1s4 - S********D 1.56 TB (1.37 TB free)

Journaled HFS+

Mount point: /Volumes/S********D

disk2 - M****D 1.56 TB (1.37 TB free)

Journaled HFS+

Mount point: /

Network:

Interface en0: Ethernet

Interface en4: iPhone

Interface en6: iPhone 2

Interface en1: Wi-Fi

802.11 a/b/g/n

Interface en5: Bluetooth PAN

Interface bridge0: Thunderbolt Bridge

System Software:

macOS High Sierra 10.13.6 (17G65)

Time since boot: About 5 days

Configuration Profiles:

Information not available

Security:

Unsigned Files:

Launchd: /Library/LaunchDaemons/com.oracle.java.Helper-Tool.plist

Executable: /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Resources/Helper-Tool

Details: Exact match found in the whitelist - probably OK

Launchd: /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Resources/com.oracle.java.Helper-Tool .plist

Executable: /Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Resources/Helper-Tool

Details: Exact match found in the whitelist - probably OK

32-bit Applications:

15 32-bit apps

System Launch Agents:

System Launch Daemons:

Launch Agents:

Launch Daemons:

User Launch Agents:

User Login Items:

MagicPrefs (? - installed 2018-07-28)

(/Applications/MagicPrefs.app/Contents/MacOS/MagicPrefs)

iTunesHelper (Apple - installed 2018-07-28)

(/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app/Contents/MacOS/iTunesH elper)

Internet Plug-ins:

FlashPlayer-10.6: 30.0.0.154 (installed 2018-08-20)

Flash Player: 30.0.0.154 (installed 2018-08-20)

QuickTime Plugin: 7.7.3 (installed 2018-07-04)

JavaAppletPlugin: Java 8 Update 181 build 13 (installed 2018-09-03)

AdobeAAMDetect: 3.0.0.0 (installed 2018-08-04)

npSurveillancePlugin_1.0.0.796: SurveillancePlugin_x86_64 1.0.0.796 (installed 2018-09-04)

3rd Party Preference Panes:

Flash Player (installed 2018-07-28)

Java (installed 2018-07-07)

Time Machine:

Time Machine Not Configured!

Performance:

System Load: 1.43 (1 min ago) 1.35 (5 min ago) 1.42 (15 min ago)

Nominal I/O speed: 0.21 MB/s

File system: 22.90 seconds

Write speed: 188 MB/s

Read speed: 447 MB/s

CPU Usage:

Top Processes by CPU:

Top Processes by Memory:

Top Processes by Network Use:

Virtual Memory Information:

Software Installs (past 30 days):

End of report