if its at the cellar i'm still hear the noise, also if a put my Hand behind the second fan its pretty hot, so my question is how to set the fan speed down cauz i wanna cool down the Chips with watercooling
It looks like you are keeping your unit in a very closed space without air circulation. If that is the case, then the water-cooling may not work properly either. I'd first make sure the cellar has good ventilation, at the very least an exhaust ventilation where you can point the blowing fan(s) to. If that is OK then:
1. First install your water-cooling, and when that is working properly, then the fan speed will automatically reduce. This will reduce the fan noise.
2. If the fan speed does not reduce and you are sure the watercooling is working very well, then open the S3 box and pull out the fan connections. This will stop all the noise from the fan.
EDIT: PS. I wrote the above with a straight face.