@magnet
its not like that there is a reason why i havent recommended a 500W
power supply.
For saying its very easy 500Rs more for the 500W Power Supply get it.
But let me tell you Why?
His PS has to feed the Motherboard,CPU,6600GT GPU,1 or 2 HDD's,1 or 2 DVD-Rom or DVR-Writer
for this much a 400W Power supply is more tha enough
Thats it.
A 500W power supply can feed
Mobo , CPU , 2PCIx16 GPU, 4-5 SATA HDD's , 2Optical Drivers
or even more devices
If this much amount of power is not utilized that power is converted to Heat and hence the PS gets heated and hence the PS Fans rotate at a high speed since the temp is high in the PS so it is need to cool.But the Heating
of the power supply is not good sign.and also wastage of power.
So i told him to go for a 400W PS
I hope this answers your doubt