Yeah, well not according to this guy:
"Well I highly reccomend you cancel your order. I would get the 500w if you have the 4850, you need 40A to run your system with that card.
The 430w only have 34A.
If you have gotten the 4770, then you can use the 430w.
The 430 with your system, will but alot of stress on that PS, which will cause hardware failure, that will lead to more costly problems.
I hope you understand, I have been doing this for over 20years."
Is he correct?
No. The 4850 only uses ~10A. The rest of your system is probably another 10A.
And the EA430 is only 30A 12V, while the 500W is 34A not 40.