mat3 vs mat4 speed

[divide]

Hello

Is it faster to compute mat3 or mat4 operations in fragment programs ?
I'm asking so because I guess GPU is optimized for mat4 operations rather than mat3..

Thanks

[Relic]

mat4 * vec4 takes one instruction more than mat3 * vec3, if that answers your question.

[divide]

Ok thanks, so if I can I should rather use mat3 operations.

[divide]

Seems that Mat3*Mat3 operations are faster than
3 Mat3*Vec3 operations, interesting !

[CobraMantis]

How can that be?!