Difference between 945 and 965 chipsets

[jensmose]

Hi
I develop an embedded graphic application. We have two different HW platforms. One with a 965 chipset and a downgraded system with a 945 chipset. A lot of the code is the same for the two platforms, including all the DirectX code for setting up the graphics engine. Now one of my carefull testers have taken exactly the same input data, exactly the same code and great wunder: the resulting image is not identical. In some pixels there is a difference of 1 inone of the color channels!
The shader is very simple. It looks up in a luminance L8 texture and then applies a color from a L8 color map texture.
The vertex pattern is just a simple square.
I guess it is some difference in the rounding calculation circuit between 945 and 965.
Can this be confirmed from Intel or is there an other explanation.

[Chuck_De_Sylva]

Quoting - jensmose

Hi
I develop an embedded graphic application. We have two different HW platforms. One with a 965 chipset and a downgraded system with a 945 chipset. A lot of the code is the same for the two platforms, including all the DirectX code for setting up the graphics engine. Now one of my carefull testers have taken exactly the same input data, exactly the same code and great wunder: the resulting image is not identical. In some pixels there is a difference of 1 inone of the color channels!
The shader is very simple. It looks up in a luminance L8 texture and then applies a color from a L8 color map texture.
The vertex pattern is just a simple square.
I guess it is some difference in the rounding calculation circuit between 945 and 965.
Can this be confirmed from Intel or is there an other explanation.

Hmm, could be a possble driver bugthough getting a fix in such an old part as 945 will be next to impossible. Can you post your simple shader possibly?