Thanks for your explanation Maxim.

I think the results are not correct because I switch off nginx and values come correct again. I swich on nginx and I get weird values. That is why.

You said:
>The fact that Apache's cpu usage is different from what you have
>without nginx might have many reasons. Possible ones are ranging
>from incorrect Apache configuration which causes neeedless process
>startup/shutdown (which now happens more often due to low worker
>process utilization) to just a simple fact that your system
>handles more requests now (and consumes more CPU as a result) due
>to no longer being limited by some other resource.

Any tip, clue or url to start investigating about this?

>This is normal, as working with slow clients is offloaded to nginx
>now. Apache processes are no longer busy waiting for a client
>to sent rest of a request or read another part of a response.

Thanks! I understand now!

Regards.