Commentary:

ATI seems to have picked up the pace on Linux driver support. The latest driver will actually build without issue on vanilla kernel.org kernels. Fast readback is only enabled currently on FireGL hardware. To get the readback performance discussed here, you need to use FireGL's or have a chat with the folks at ATI.

Performance:

Readback performance:

RGBA: 864MB/s (1024x1024)

Volume rendering performance with Raptor:

2D transfer function, central differencing gradient calculation, Blinn-Phong lighting

Gige: 1.5GVox/s

Infiniband (SDP+AIO): 8GVox/s

512x512x1024 CT Volume