My New Macbook 12" Retina runs hot sometimes and battery isn't lasting as long as it did when I first purchased 3 months ago...

Time since boot: About 40 days

As much as it pains me to say this, "Reboot" every once in a while.

It pains me because I come from a generation of computer professionals that believes that rebooting is an evil thing, and we took pride when the operating system was up for months at a time running stable. Unfortunately, not since Snow Leopard 10.6 has macOS been that stable.

So reboot every once in a while, especially if you are seeing performance issues after being up for 40 days and 40 nights.

Google Chrome is a resource hog, and you have 20'ish tabs open. Each of those tabs could have active Javascript running in them that can be letching CPU, Network, and memory resources even when they are not the tab being displayed. And as each tab is from a different website, there can be 20'ish different ways for those websites to play nice or be lazy about how they use your resources.

While your Macbook has a generous amount of RAM (16GB) you have still managed to fill it up and started using the swap files on your SSD. While an SSD is much faster than the old rotational hard disks, it is still not as fast as keeping your code and data in memory.

Try cutting back on the number of apps you keep open and running. Cut back on the number of browser tabs you keep open. Maybe look at using Safari or Firefox (if there is some website that only likes Chrome, you can always just use Chrome for that website, and another browser for the rest).

If you are going to keep Chrome, maybe look at "The Great Suspender"

<The Great Suspender - Chrome Web Store>

as a way to tame all the tabs, you are keeping open.

A Troubleshooting Procedure that may Fix Problems with macOS El Capitan or Later

You should try each, one at a time, then test to see if the problem is fixed before going on to the next.

Be sure to back up your files before proceeding if possible.

1. Shutdown the computer, wait 30 seconds, restart the computer.
2. Disconnect all third-party peripherals.
3. Resetting your Mac’s PRAM and NVRAM
4. Reset the System Management Controller (SMC)
5. Reset your Startup Disk and Sound preferences.
6. Start the computer in Safe Mode. Test in safe mode to see if the problem persists, then restart normally. Also, see Use safe mode to isolate issues with your Mac - Apple Support and Playing Safe- what does Safe mode do?.
7. Use Apple Hardware Test to see if there is any hardware malfunction. How to invoke and interpret the Apple hardware tests - CNET.
8. Repair the disk by booting from the Recovery HD. Immediately after the chime hold down the Command and R keys until the Utility Menu appears. Choose Disk Utility and click on the Continue button. Select the indented (usually, Macintosh HD) volume entry from the side list. Click on the First Aid button in the toolbar. Wait for the Done button to appear. Quit Disk Utility and return to the Utility Menu. Restart the computer from the Apple Menu.
9. Repair permissions on the Home folder: Resolve issues caused by changing the permissions of items in your home folder.
10. Create a New User Account Open Users & Groups preferences. Click on the lock icon and enter your Admin password when prompted. On the left under Current User click on the Add [+] button under Login Options. Setup a new Admin user account. Upon completion log out of your current account then log into the new account. If your problems cease, then consider switching to the new account and transferring your files to it - Transferring files from one User Account to another.
11. Download and install the OS X El Capitan 10.11.6 Combo Update or 10.12.6 Combo Update or Download macOS High Sierra 10.13.6 Combo Update as needed.
12. Reinstall OS X by booting from the Recovery HD using the Command and R keys. When the Utility Menu appears select Reinstall OS X then click on the Continue button.
13. Erase and Install OS X Restart the computer. Immediately after the chime hold down the Command and R keys until the Apple logo appears. When the Utility Menu appears:

1. Select Disk Utility from the Utility Menu and click on Continue button.
2. When Disk Utility loads select the drive (out-dented entry) from the Device list.
3. Click on the Erase icon in Disk Utility's toolbar. A panel will drop down.
4. Set the Format type to APFS (for SSDs only) or Mac OS Extended (Journaled.)
5. Click on the Apply button, then wait for the Done button to activate and click on it.
6. Quit Disk Utility and return to the Utility Menu.
7. Select Reinstall OS X and click on the Continue button.

14. If none of the above helps then see How to Downgrade macOS High Sierra and macOS Reversion- How to Downgrade from High Sierra.

15. If you get here without success then make an appointment at the Apple Genius Bar for service. If you need to find an Apple Store - Find a Store - Apple.

Ways to help make a slow Mac faster

1. 17 Reasons Why Your Mac Runs Slower Than it Should
2. Slow Mac Performance? This Article Solves It!
3. Fix slow start-ups in OS X | MacFixIt - CNET Reviews
4. How to fix slow shutdown and startup times. | MacTip.net
5. 6 Easy Tips to Speed Up OS X Yosemite on Your Mac
6. OS X El Capitan- If your Mac runs slowly
7. Visit The XLab FAQs and read the FAQ on Performance
8. Tips to Fix Issues that affect Mac Performance
9. Avoid using any third-party cleanup software. Usually, this software does more bad than good. You don't need it. All computers become slower over time even under normal use. Experienced users erase the hard drive and do a clean install from scratch from time to time; or whenever installing a major OS upgrade. Doing so means you must maintain regular and multiple backups.
10. If you have enabled iCloud Disk and are storing your Documents and Data in iCloud, then consider turning that off and signing out of iCloud. It can slow down the computer considerably. Please see the following from the user, fotomac: "The solution was to SIGN OUT of iCloud and my problem STOPPED! NO MORE SPINNING BEACHBALL! My computer's speed increased to what it should be and all my Apps now work!"
11. Add more RAM or cut back on the number of concurrently running applications and utilities. Remove unnecessary anti-malware software and any software that promises to clean your Mac. Check for runaway processes: Runaway applications can shorten battery runtime, affect performance, and increase heat and fan activity. Also, visit The XLab FAQs and read the FAQ on dealing with The Spinning Beach Ball of Death.
12. The Ultimate Fix: Backup everything, erase the drive, reinstall OS X, and restore your data from the backup. Reinstall third-party software from original media/scratch.

kater8067 wrote:

Thanks @bobharris. How do I run fewer apps on chrome ? Not sure what that part means. The rest I will try !

That (22) following Chrome in the EtreCheck report is a separate Chrome process, and that generally means you have that number of Chrome tabs active with each tab most likely visiting a different website. Where a tab is all of these things:

As for app (Applications) I mean Microsoft Word, Microsoft Excel, Microsoft PowerPoint, Microsoft OneNote, TeamViewer, Chrome, Apple Messages (aka iMessage), etc... EtreCheck does not list all the apps that are currently running on a system, it just lists the top resource users.

Many apps on the Mac do NOT quit when you close the last window. They keep running. And some apps do quit when you close the window. That is a per app decision on how it wants to behave.

But if you have been closing windows thinking that Quit the App, then you still have apps running even though you are not using them. To properly quit an app, you use the App menu and select Quit or

Do you think my ICloud is slowing it down as well?

If iCloud were slowing you down, it would be a top network consumer. It is not listed as a heavy users in the EtreCheck output.