Have I got what it takes to run a Radeon 295X2?

I'm sniffing at a 295X2, but I'm unsure if it's advisable to go that route. Thing is, I've got a somewhat unusual system, set up like this:



MSI Big Bang X-Power II

I7 3820 @ 4.25GHz

4 x 8GB DDR3

GTX 970

3 x SSD

3 x HD

Raid Card

- powered by a Cooler Master VSM750



And:



8 x 2TB HDs

10 x 120/140mm fans

- powered by a Corsair CX600M



The CX600M is really only there to provide additional connectors, or have been up until now.



The M/B has two 8-pin power sockets, one of which is hooked up to either PSU. Thing is, while I'm thinking the VMS750 wouldn't cut it alone when it comes to powering a 295X2 (and every PSU calculator seems to agree with me), I don't know how the CX600M alters the equation. I chose it because it was cheap, reasonable quality and because in the current set-up it isn't asked to work very hard. I'm guessing it never has the need to deliver even 150W, while the VSM750 probably reaches 350W max excluding the video card. In other words there ought to be 850 "spare" watts to play with.



But again; I haven't got a clue how my two PSUs will perform vs a single large one when it comes to powering a 295X2.



Can anyone enlighten me?

Have I got what it takes to run a Radeon 295X2?