Then there's the GTX 480. I have no way of comparing apples to apples between the 7850 and 480, since AnandTech's compare utility has the 480 in the 2011 GPU list, and the 7850 in the 2012 list. The 480 benchmarks against older games so it's not a fair comparison... but like I said earlier, Passmark ranks it highly.
Is the 7850 the right move in the $250 price range?
Well first off, I'm sorry no one replied to you before the shipping date but be at ease you made a good decision in purchasing the radeon 7850. The 650watt power supply is enough for your needs be it for the radeon 7850 or the gtx 570.
Although the gtx 570 beats the radeon 7850 in some games the radeon 7850 is the better bang for the buck. Because it uses less power, runs 10C cooler at full load and well its cheaper.
I, myself recently purchased a radeon 7850. The reason is that the gtx 570 has 1.25gb of vram while the radeon 7850 has 2gb making the radeon 7850 the one that can play future games at high settings (games are taking more vram with each passing year). Furthermore if your into overclocking the radeon can overclock easily to 1050Mhz. In conclusion dont be put off becausew the gtx 570 outperforms the rddeon 7850 in some game. Still facts speak better thatn opinions so here is the link to the review and and comparation of the gtx 570 and radeon 7850 http://pcper.com/reviews/Graphics-Cards/AMD-Radeon-HD-7...