When I assign values to vectors in effect files, those values do not seem to be loaded when I actually use the effect file in my own code. Here's an example of what I mean. I have an effect file with simple pixel shader that looks like this: . . . float4 myColor = ( 0.00, 1.00, 0.00, 1.00 ); float4 ps_main(in float3 Color : TEXCOORD0) : COLOR0 { return( myColor ); } . . . My expectation when I load this effect using Effect.FromFile (in an MDX app) and draw a simple model using the effect, is that the model will be drawn in all green. What actually happens is the model is drawn in all white instead. When I check the value of the myColor parameter immediately after loading the effect like this: ColorValue test = m_paintEffect.GetValueColor("myColor"); Sure enough, I find that the value is always {1.0,1.0, 1.0,1.0} This only seems to be the case with vector type global variables. Other variable types seem to have their values set when the effect file is loaded. What am I doing wrong here?