My Imac retina 5k is extremely slow and does not respond as it should. I especially have problems surfing the internet.

I purchased my Imac less than a year ago and it seemed to be working just OK in the beginning.
I did download some torrents, and removed those later. I also installed a game of the sims which I also uninstalled. I believe that is when the mac started to slow down. It has only gotten worse, I installed cleanmymac in an attempt to speed it up and get rid of malign files. That does not seem to help much. I notice with this app that my RAM memory is almost always full. I have difficulties on the web, I cannot open some simple websites like www.couchsurfing.org. Others take minutes to open. I stream radio with my mac which works fine sometimes, while other times it is completely interrupted, especially if I try to connect it with an external speaker via bluetooth.

I am by no means a mac expert and would really love to get some insights.

I have ran Entrecheck and this is what it came up with:

EtreCheck version: 3.0.6 (315)

Report generated 2016-10-17 23:54:28

Download EtreCheck from https://etrecheck.com

Runtime 1:48

Performance: Excellent

Click the [Support] links for help with non-Apple products.

Click the [Details] links for more information about that line.

Problem: Computer is too slow

Description:

My Imac is extremely slow and does not respond as it should. I especially have problems surfing the internet.

Hardware Information: ⓘ

iMac (Retina 5K, 27-inch, Mid 2015)

[Technical Specifications] - [User Guide] - [Warranty & Service]

iMac - model: iMac15,1

1 3,3 GHz Intel Core i5 CPU: 4-core

8 GB RAM Upgradeable - [Instructions]

BANK 0/DIMM0

4 GB DDR3 1600 MHz ok

BANK 1/DIMM0

4 GB DDR3 1600 MHz ok

BANK 0/DIMM1

Empty

BANK 1/DIMM1

Empty

Bluetooth: Good - Handoff/Airdrop2 supported

Wireless: en1: 802.11 a/b/g/n/ac

Video Information: ⓘ

AMD Radeon R9 M290 - VRAM: 2048 MB

iMac 5120 x 2880

System Software: ⓘ

macOS Sierra 10.12 (16A323) - Time since boot: about 16 hours

Disk Information: ⓘ

APPLE HDD ST1000DM003 disk0 : (1 TB) (Rotational)

EFI (disk0s1) /private/var/tmp/MPKSSF6R : 210 MB (182 MB free)

Recovery HD (disk0s3) <not mounted> [Recovery]: 650 MB

Macintosh HD (disk1) / [Startup]: 999.03 GB (725.43 GB free)

Core Storage: disk0s2 999.35 GB Online

USB Information: ⓘ

Apple Inc. BRCM20702 Hub

Apple Inc. Bluetooth USB Host Controller

Apple Inc. FaceTime HD Camera (Built-in)

Thunderbolt Information: ⓘ

Apple Inc. thunderbolt_bus

Gatekeeper: ⓘ

Mac App Store and identified developers

Kernel Extensions: ⓘ

/System/Library/Extensions

[not loaded] com.avira.kext.FileAccessControl (1.1.1 - SDK 10.9 - 2016-10-15) [Support]

System Launch Agents: ⓘ

[failed] com.apple.security.cloudkeychainproxy3.plist (2016-08-30)

[not loaded] 6 Apple tasks

[loaded] 168 Apple tasks

[running] 95 Apple tasks

[killed] One Apple task

one process killed due to insufficient RAM

System Launch Daemons: ⓘ

[not loaded] 42 Apple tasks

[loaded] 158 Apple tasks

[running] 101 Apple tasks

[killed] 2 Apple tasks

2 processes killed due to insufficient RAM

Launch Daemons: ⓘ

[loaded] com.adobe.fpsaud.plist (2016-09-24) [Support]

[loaded] com.macpaw.CleanMyMac3.Agent.plist (2016-05-29) [Support]

User Launch Agents: ⓘ

[loaded] com.macpaw.CleanMyMac3.Scheduler.plist (2016-10-14)

[not loaded] org.hola.vpn.plist (2016-08-16)

User Login Items: ⓘ

Flux Application (/Applications/Flux.app)

Internet Plug-ins: ⓘ

FlashPlayer-10.6: 23.0.0.185 - SDK 10.9 (2016-10-11) [Support]

QuickTime Plugin: 7.7.3 (2016-08-30)

Flash Player: 23.0.0.185 - SDK 10.9 (2016-10-11) [Support]

JavaAppletPlugin: 15.0.1 - SDK 10.12 (2015-11-29) Check version

3rd Party Preference Panes: ⓘ

Flash Player (2016-09-24) [Support]

Time Machine: ⓘ

Time Machine not configured!

Top Processes by CPU: ⓘ

6% firefox

3% WindowServer

3% fontd

2% kernel_task

1% sysmond

Top Processes by Memory: ⓘ

1.00 GB firefox

909 MB kernel_task

254 MB Finder

238 MB Mail

205 MB mdworker(10)

Virtual Memory Information: ⓘ

1.95 GB Free RAM

6.04 GB Used RAM (2.08 GB Cached)

78 MB Swap Used

Diagnostics Information: ⓘ

Oct 17, 2016, 07:03:09 AM Self test - passed

Oct 16, 2016, 09:35:06 PM /Library/Logs/DiagnosticReports/firefox_2016-10-16-213506_[redacted].cpu_resour ce.diag [Details]

/Applications/Firefox.app/Contents/MacOS/firefox

Oct 15, 2016, 09:52:58 PM /Library/Logs/DiagnosticReports/mds_stores_2016-10-15-215258_[redacted].crash

/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/Metadat a.framework/Versions/A/Support/mds_stores