I went by, "can I run CivIV?". If so, then GalCiv2 runs fine.
From the box:
minimum - 800Mhz, 256 RAM, 32MB DirectX 9.0c vid card
recommended - 1.8Ghz, 512 RAM, 128MB DirectX 9.0c vid card
From experience the 9.0c vid card is the key. Since 9.0c just came out you'll need new drivers, like less than a month old drivers.