How do you set up 2 monitor exactly the same colours?

[bibo]

I have a Matrox P750 and I use it for video editing and CG in general.
I have 2 19" Compaq CRT monitors and I would like to set them up so they display exactly the same colours.
I have used DisplayMate (a powerful professional utility to analayse monitors) in combination with PowerDesk utility (fine adjusting RGB's Gamma), but I do not achieve the desired results - the Whites or Blacks of one monitor are always different from the other one. This is very apparent when I stretch any window over the 2 monitors: the background, either white or grey, is always visibly different between the 2. This is quite bothering!

Have you managed to perfectly adjust your 2 monitors?
How did you do it?
Do I have to use an external hardware Spectrophotometer?

Thanks.

Bibo

[gt40]

I think I'm seeing triple

[Kruzin]

Please don't cross-post the same thread in multiple forums. Once is enough.
As this is not directly Matrox related, and you have gotten a reply in your General Hardware copy of this post, this copy will be closed.