Continue to this: Topic:U1sl12b4w1gkbh2k ( I couldn't write this as a respone, please move it there )
Ok,
I figured it was two bug that was limit the system, so when google start to crawl it made DDoS.
I solved it by do two steps.
- Set limitation InstanceMaxRequests PHP_FCGI_MAX_REQUESTS, to 80 [EVEN THOUGH THE RECCOMENDATION IS 8 PER CPU CORE ON IIS IT MUST BE HIGHER!]. - That solved the cpu and ram issue.
- I changed the aplication pool user and the websites auth to be the same user - that stopped the random error 500.
I hope it would help someone in the future.
Thanks again for your directions.