is there more to using a previous shader than changing the version numbers? i have no geometry shader and these are my pixel and vertex shaders: PS_IN VS( VS_IN input ) { PS_IN output = (PS_IN)0; output.pos = input.pos; output.col = input.col; return output; } float4 PS( PS_IN input ) : SV_Target { return input.col; } but when i try to change the version to 3 ie usercontrol.g_pEffect = D3D10.Effect.FromMemory(usercontrol.g_pd3dDevice, WPViewDX.Resources.Tutorial07, "fx_4_0",D3D10.ShaderFlags.EnableStrictness, D3D10.EffectFlags.None, null, null); SetVertexShader( CompileShader( vs_4_0, VS() ) ); SetPixelShader( CompileShader( ps_4_0, PS() ) ); ==> usercontrol.g_pEffect = D3D10.Effect.FromMemory(usercontrol.g_pd3dDevice, WPViewDX.Resources.Tutorial07, "fx_3_0",D3D10.ShaderFlags.EnableStrictness, D3D10.EffectFlags.None, null, null); SetVertexShader( CompileShader( vs_3_0, VS() ) ); SetPixelShader( CompileShader( ps_3_0, PS() ) ); it crashes saying A first chance exception of type 'SlimDX.Direct3D10.Direct3D10Exception' occurred in SlimDX.dll Additional information: D3DERR_INVALIDCALL: Invalid call (-2005530516)