For a GPGPU application, I’m summing up some floating point numbers (say, in the order of 500 floats) to a render target. What concerns me: On pre-G70 NVIDIA cards (FX4400, FX3400, GF 6800), the results are exactly the same. On G70-based cards (7800 GTX, FX 4500) results vary compared to the pre-G70 results in the order of about a tenthousandth part. How can this be? What does the G70 do differently? Which results are to be considered more “correct”?
Thanks for any insights.