Are you on shared hosting/ VPS/ metal?
Are you using any additional K2 extensions?
From a Joomla! debug printscreen it is impossible to pinpoint the issue.

modK2ContentHelper::getItems() Can you send me the settings for this instance of K2 Content?

Thank's for reply.

1 - We are on a VPS

2 - List of k2 extensions :
- Sj K2 Slideshow
- Mod Bt_content_slider
And you're Mod_k2_Content module

3 - Link to lutim for screenshots : lut.im/gallery#dztUJTbWP7/5sQMaVDTUiMtwyei.jpg,NwMrPvUb2C/A8qRuIllovFWoMI2.jpg,QpD093M4WX/wOezvxB9PCweHqdY.jpg,txMhZonXBD/HwhSqJRDIpcdzNwY.jpg

I am trying to replace all btcontentslider modules with the K2 Content module.
I did not know that they could create different templates.
I try and tell you if it works better.
If you ever have any advice do not hesitate.

(Sorry for the Google translate...).

Regards,
Charly

Let me know, also do send me your server's specs.
If your server is underpowered and you have high traffic maybe an upgrade or a CDN is the way to go.

We have a CPU Xeon E5 (i don't have the exact model)
Ram : 16GB physical and 16GB virtual
500GB SSD Disk

We have 20 000 visitors per day and approximately 200 visitors at the same time and the maximum record is 300.

I have replace a lot of instances of Bt_Content_Slider and the performances are better.

Nice to hear this :)
That's a nice machine, you can also experiment with caching and tweak its settings for peak performance.

Hi, Durand! With those specs your site should be flying! We have a pretty similar site with real time 300-500 active sessions and some 130 000 to 160 000 pageviews on average day.

We have been using K2 for reasons dating back to 2011 and we have had to do some code modifications to get our site in working order. Adding processing power and playing with cache just doesn't cut it. The problem lies deeper.

We have found couple of big resource hogs in the code and we have manually fixed those. Grab a coder somewhere to help you and check this thread: www.joomlaworks.net/forum/k2-en/47858-solved-k2-query-cache-problem#163417

We also had to do the same trick for K2 Images.

And other fix we implemented rose just recently as we moved our site to Amazon AWS: Many of K2 tables use MyISAM as engine and that causes table locks. We suffered a lot of table locks that caused the php-fpm to spawn max childs and then the site went unresponsive for 2-5 minutes until the locking opened. No resource can handle that.

The solution for us was to first convert the table K2_items to innoDB engine. We are converting the rest of the K2 tables to innoDB shortly.

That solved the problem and we have had no table locks since then.

I don't know what are the plans in K2 development are and if Krikor and his colleagues taking notes from these, but currently the underperforming of the component is a huge problem for us in conjunction to the silence around component development and we have started a project to find and alternative.

I hope these help you in your site performing issues!