I bought
- Thermaltake smart case fan II (80x80x25mm)
http://shop.freezinghardware.nl/index-info.asp?ID=478
- Thermaltake vga Geforce 4 cooler
http://shop.freezinghardware.nl/index-info.asp?ID=453
- 12 to 9,5 volt converter
http://shop.freezinghardware.nl/index-info.asp?ID=229
I have replaced the system fan by the Thermaltake and have it connected to systemboard fan 3 connector.
I have replaced the asus cooler by the thermantake, plugged in the 12 to 9 volt converter and have connected it to systemboard fan 1 connector.
In the system bios I have enabled smart fan option. This option reduces both fan 1 and 3 speed if system temperature is below 78 degree celsius.
This results in a nearly silent system. I have checked both cpu's; temperature is at an acceptable level!