Is dual power supply's feasable

[diven nuttall]

Hi i am trying to figure out if i should use 2 power supply's or 1, I have no money to spend. OK so here are the specs:
GPU: HD 5770; max power consumption 110w
CPU: Q9550 max power consumption 95w
Main power supply: HP oem psu 365w dual 12v rails 14A for cpu and 12A for rest of system 280w all up combined 12v power.
Spare power supply: Dell oem psu 280w single 16A 12V rail so 170w 12v power

I have used multiple power supply calculators and they all said i was 100w under my Hp power supplys max watts. Im 95% sure that the system will run fine on the single hp power supply. So basically my question is in your guys opinion should i just use the one power supply or should i use both of them and dedicate the Dell one to my gpu. I know how to wire them up correctly to turn on at the same time so all i need to know is that wich set up would be better for the power supply(s) and the gpu/cpu?

Oh and anyone's experiences with dual powers supply's is much apprenticed.

 

[Emerald]

One PSU will do the trick.

 

[diven nuttall]

One PSU will do the trick.

Are you sure because when i calculated the power for the rest of the system (excluding the cpu and gpu it was only 35w minus 15w for hdd= 20w for fans/motherboard. Is this enough.

 

[diven nuttall]

OK im going with the one power supply thanks for your answer, i just wanted some body else opinion.