9 years Mac user, never had any issue until Mojave!

[animatedude]

First of all. I leave my computers running 24/7 and have for the last 26 years. I worked IT and was a network manager in a previous life and have never shut my computers down every day. I find in some instances my computers seem to last longer than those that are shutdown everyday. Just my observances.
For the gentleman that suggested to turn off computer sleep in energy saver, I second this.

Now on to the OPs original problem. Are you experiencing lock ups and such while you are using it? Or is it just confined to sleep? I will tell you my 27" 2010 iMac started off with sleep problem you describe and then later on progressed to lockups and kernel panics. It was all traced down to a failing GPU because of the amount of heat generated by the larger iMacs. Not sure if this is your issue or not, just throwing it out there.

Hmm and how did you deal with that?

Now the problem is back but it's not as bad as before, it only happened like twice this week...for example today i woke up my iMac and it was fine

If you read the results above, i highlighted a minor problem "Heavy I/O usage - Your system is under heavy I/O use. This will reduce your performance".

I got this result after i allowed full access to my computer, any idea what does it mean?

 

[verdejt]

No I'm not sure. Like one poster said run activity monitor. Here is a link to another software vendor's instructions on how to capture a sample of activity monitor. https://marinersoftware.deskpro.com/kb/articles/how-to-capture-a-sample-from-activity-monitor

How I fixed my problem was to purchase a 2010 MacPro and sell the 27" iMac. It was cheaper in the long run. The estimate to replace my video card was about 900 USD (about 500-600 of that was the cost of the video card). Even then I read where they only last a couple of years before going out again. So I sold it on Let It Go for about 150 to a guy who was buying it for niece to do her school work. To my knowledge it never locked up on him. Probably because he was doing intense video stuff like I was doing. My MacPro was about 800 dollars. 200 of that was because I needed to upgrade the video card to a Mac EFI version that supported Metal. Still it was a steal. Everyone I've looked at with my specs runs about 1700 USD.

Not sure if your problem is the same as mine but it was a known problem with the 2010 27" iMacs.

 

[animatedude]

I noticed in the activity monitor a user named root, does it have any effects on the CPU? why does it exist if i'm the only one using my iMac...

 

[verdejt]

Root is a user that is required. It's running all the basic stuff that is required by MacOS to run. You want to look at %CPU and see which one is high.

 

[animatedude]

[doublepost=1545879157][/doublepost]Noticed anything wrong, sir?

 

[verdejt]

Nope mine has the kernel_task as well. You have a lot of google Chrome helper running at the same time. That is the first thing I noticed. Trying closing chrome and see if the helper is still running.

 

[animatedude]

[doublepost=1545942352][/doublepost]what do you think? thats's after i closed chrome..

 

[verdejt]

How does it run after closing Chrome?

 

[animatedude]

It runs OK man, even when i open many Chrome tabs and leave them open.

The problem didn't happen in the last couple of days, not even once. but it will suddenly like it did last week

I think someone needs to pay attention more to the"Heavy I/O usage - Your system is under heavy I/O use. This will reduce your performance". and understand what it means