I have 400watts PSU, for AMD PhenomX4 9850, 2.5GHz

As vague as you are, the best I can say is it should.

400 generic = no
400 branded = plenty, aslong as your using say onboard/basic video card, 1 hdd, 1 dvdrw etc

Your motherboard will burn up long before your power supply

 

Should not be a problem at all --- under-volt it a notch if you are concerned.

Mobo support may be limited somewhat on AM2, but you should be good overall on AM2+ with better performance on motherboards with sb710-50.

Thanks for the reply bro.
I do not use any Graphics card, my processors socket is AM2+ and PSU is corsair 400w. and 4GB of DDR2 RAM

Thanks for the reply bro.
I do not use any Graphics card, my processors socket is AM2+ and PSU is corsair 400w. and 4GB of DDR2 RAM