I prefer running crossfire on AMD so I'll put my vote in for that. Unless you want to use CUDA or something ATI will be better.
The 6870 performs similar but scales better in CF giving it a good lead over the 470s. The 470s also draw more power which means a bigger PSU.
Why are you getting a 1000W? Also from a dodgy brand. You'll be running at about 35% load maxed which means you'll get poor efficiency. Get a quality 650W if your getting the 6870s and you will be much better off.
You could replace the board with a 890GX as the FX has x16/x16 crossfire which is not needed unless running more then 2 cards. x8/x8 is perfectly fine for anything less then 2 5970s.
Yeah. I realize those games don't require much, but in the future I may want to try some other stuff and would like to have good performance. I don't plan on doing SLI or Crossfire right away. I would just like to have the capability. The choice of motherboard between the two I listed determines if I do SLI or Crossfire and I'm just trying to figure out the better route between the two.
And yes that would be great if you could recommend some! Thank you!
Then theres a nice Roswill one for only $60 though and I will reccomend this over the antec. It ranked number 2 same as the Antec which means:
"*Rank 1 never has more than 5 units in a given power range, and is the best.
*Rank 2 has PSUs that are almost as good as those in rank 1. Maybe they were bumped out of rank one, or maybe they were placed there because of similarities to former rank 1 units.
*Rank 3 has PSUs that are good, passing all tests, but not remarkable, or with minor flaws. " http://www.newegg.com/Product/Product.aspx?Item=N82E168...
^The Rosewill PSU you listed only has two PCI-E connectors (I personally wouldn't trust two molex to PCI-E off the same PSU); if you plan to CF, you will need two per card (assuming 6850/70). With that requirement in mind, the Antec would be the best choice.
Each normal (6-pin) PCI-E connector is rated to supply up to 75 Watts, which means one adapter will pull up to 75 W. If you run two simultaneously, you're running up to 150W over one pin of the molex (we only care about the 12V line here, since that's all the graphics card uses). Molex is only rated to carry up to 11 amps per pin (this translates to 132 W), but besides the graphics card, you may also have some fans and possibly LEDs being powered too, which we'll say collectively draw 12 W. That leaves 120 W to power 150 W, which is beyond the molex spec (that can cause random shutdowns in good PSUs, or electrical fires in ones that don't properly regulate their power usage).