Just got this reply from Brian Jacobson clearing up the issue of 128mb vs 256mb graphics cards:
The game will run fine on a 128 MB card. Most of the benefits of the 256 MB cards you'll see we expect will be more long-term, received via updates over Steam:
1) Something which happens immediately, we're able to store more data on the card instead of in AGP memory, which you might think would be a perf win, but so far, we're not finding ourselves to be AGP bus-bandwidth limited.
2) We expect to release a local-specular solution, perhaps at ship, perhaps over Steam at some point, which is a major texture memory consumer. In addition, we've made it easy for major HW vendors to write new shaders for us to take advantage of the extra memory.
3) A *lot* of memory is consumed by normal maps, since they can't be compressed well. We may ship uncompressed normal maps for the 256 MB cards if it turns out to be a big enough visual improvement. Future updates (not to mention mods) will contain high-end content that use ever-larger amounts of normal maps.
The game will run fine on a 128 MB card. Most of the benefits of the 256 MB cards you'll see we expect will be more long-term, received via updates over Steam:
1) Something which happens immediately, we're able to store more data on the card instead of in AGP memory, which you might think would be a perf win, but so far, we're not finding ourselves to be AGP bus-bandwidth limited.
2) We expect to release a local-specular solution, perhaps at ship, perhaps over Steam at some point, which is a major texture memory consumer. In addition, we've made it easy for major HW vendors to write new shaders for us to take advantage of the extra memory.
3) A *lot* of memory is consumed by normal maps, since they can't be compressed well. We may ship uncompressed normal maps for the 256 MB cards if it turns out to be a big enough visual improvement. Future updates (not to mention mods) will contain high-end content that use ever-larger amounts of normal maps.