Geforce 7 series power requirements? (7900GS 512mb)

[N7_RiZe]

Hey everyone!

I'm currently upgrading the pc hardware in my real hardware arcade machine.
So far it works with the few upgrades I have done with it but I think I may of hit a wall with the gpu upgrade.
The stock gpu all the arcade cabs of this game come with are ASUS 7600GS 256mb and the PSU output is 'continuation maximum capacity 250W' and '300W Peak capacity'
I have just bought a PNY 7900GS 512mb for very cheap and it requires 6-pin power from the psu. (The PC will not accept anything other than the Geforce 7 series due to it's Linux drivers, if you wanted to ask) 
Obviously my question is, would the 7900GS be too much for the stock 300W psu?
So far I have looked online for the power requirements for the 7600 and 7900 but different websites list different numbers.
E.g. One website said 300w psu for a 7600 512mb, EVGA says 400w for their 7600 and CNET says 350w for a 7900GS 256mb
Any help would be appreciated.
Thanks.

[Mira Yurizaki]

If we pull from a review of the cards:

https://www.anandtech.com/show/2082/12

https://www.anandtech.com/show/1967/4

 

Total system power consumption doesn't even peak 250W, though keep in mind of what hardware they were using as well.

[N7_RiZe]

8 minutes ago, M.Yurizaki said:

If we pull from a review of the cards:

https://www.anandtech.com/show/2082/12

https://www.anandtech.com/show/1967/4

 

Total system power consumption doesn't even peak 250W, though keep in mind of what hardware they were using as well.

Thanks for this, these never came up on my searches and even though it doesn't list the two GS models, it's really helpful!