As stated on Planetside's site FAQ for min requirements:
What will the system requirements for the Windows version be?
We're still evaluating this. However, the absolute bare minimum would be any Pentium/AMD, and 256Mb of RAM might be enough. But we may have to increase these requirements by the time TG2 is released.
As always, the faster the CPU and the more RAM you have, the better.
We don't yet know what versions of Windows we can support, but Windows 2000 and Windows XP will certainly be supported.
Will TG2 require a powerful graphics card, and will it benefit from one?
TG2 will not require a powerful graphics card. However, you will certainly benefit from having one, much more so than with the current version of TG. TG2 uses OpenGL on Windows and the Mac for drawing graphically intensive parts of the user interface, such as the 3D Preview and the network view. It is not used for final rendering however.
Any recent graphics card should stand you in good stead. TG2 does not currently take advantage of the shader capabilities of advanced cards, but it may do in the future. Graphics card technology is still changing rapidly so it's hard to predict where things may end up by the time TG2 is released.