That card may have some issues with the final game, but you should still be able to crank things up pretty nicely.
As in doesn't supported needed features, or as in it doesn't have the power to run it at max?
The later most likely. I don't see supported features specs changing, but when we get the two other races in performance is sure to take a dive.
I've got only 1.7 Ghz CPU...
Will it run?
Here are the minimum and recommended specs for Sins beta 3.
Minimum: Windows XP SP2/Vista, 1.8 GHz CPU, 512 MB RAM (1 GB for Vista), 128 MB DirectX 9 3D Video Card, DirectX 9.0c or higher;
Recommended: 2.4 GHz CPU, 1 GB RAM (2 GB RAM for Vista), 256 MB DirectX 9 3D Video Card, LAN or Broadband Internet Connection for Online Multiplayer.
As you can see the bare minimum is a 1.8 GHz CPU, you may be able to run it but it likely isn't going to run well, all depending on the rest of the system as well.