is it possible to use two power supplies in a single cpu i have a 750 w psu and another 550 w psu, can i use one for gpu and another for motherboard ,also are hunt key psus good
I would recommend sticking with one PSU. If you try two different PSUs, you might need to tie the DC grounds together to avoid having them float relative to each other. Really, this can get a bit messy, so use a single PSU whenever possible.
Don't try using multiple power supplies unless you know enough about electricity to not have to ask if you can use multiple power supplies.
Huntkey power supplies are not very good. They are an actual manufacturer and the fact that no one else uses them as an OEM reflects their quality......poor.
You already have one hell of a CPU bottleneck. Get a new CPU and motherboard before adding more graphics power. With a Phenom II 945 there is no way you are even able to use your 6990 to it's potential much less more.