The vertex processors of the RADEON X1000 are designed in much the same manner as in the NVIDIA GeForce 7 architecture. Each processor consists of two units, vector and scalar, with the only difference that the G70’s vertex processors have 32-bit ALUs, while the vector ALU of a vertex processor of the RADEON X1000 is 128-bit. This feature allows emulating the central processor on the GPU.
RADEON X1800 vertex shader engine
The new vertex processors can perform two instructions per clock cycle. An ordinary shader may be as long as 1024 instructions or virtually infinite with flow control instructions. Of course, the vertex processors of the RADEON X1000 are fully compliant with the Shader Model 3.0 specification.
Theoretically, the vertex shader performance of the RADEON X1800 XT should be much higher than that of the GeForce 7800 GTX since its vertex processors work at a much higher frequency. But we can only know this for sure after we’ve tested the card in appropriate benchmarks.