Is apache working correctly?

Question

Apache HTTP Server

The bottom line is, there is a VPS on it Debian + VestaCP
2.66Mhgz x 2
1Gb Ram
4 sites are spinning on it, 2 of them on WP one on Yii2 one is just HTML
It costs NGINX statics proxying
When restarting the Apache, ~ 80-100MB of RAM is occupied.
But as soon as you start wandering around these Wordpress sites, the memory starts to fill up. And if when you enter Yii2, it seems to return or eat not so much (the site itself is easy there). Then after entering the WP sites, that’s all, several Apaches hang in htop and you can easily score the whole gig, to such a state that Debian itself starts killing processes, referring to lack of memory. Is it normal? Or is there a problem with the configs?
ps: it comes to the point that it costs several times to press f5 quickly and you can put a server and a bunch of apache appears in htop and the memory immediately reaches 950 out of 1000.

Answer 1

curve config

Answer 2

I changed everything to nginx + fastcgi because it got better)))