I read that the TDP is not consumption, well heat dissipation and PSU to pick up will not help.
TDP - thermal design power, Yes, that is the dissipation.
While the amount is not regulated by standards. Someone considers as a maximum generated heat, and some marketers with the same Intel TDP under mean higher heat generation in a test.
But heat and power consumption with a small error of the same - almost all consumed by the electronics energy is converted into heat.
And on what grounds the recommended PSU is 400 watts, if greater than 75 will not pull PCI-E x16
Recommended BP set the total system model, not just for the video card. Besides a very large stock on many power supplies is extremely doubtful properties.