Wrong refresh rate ofIiyama Vision Master 1452 on ATI HD4850

[consused]

Originally Posted by DestinationAlpha

I did as you suggested, but the xorg.0.log only contained the warning "Force AIGLX enabled" and no error messages.

Good, you found the log but what did it tell you in (II) messages, about the default modes detected on probing (module "ddc") your monitor?

It should be using that information to select the correct modes. After the probing shown in the log, you should see a lot of modes being rejected if they are outside the vertical or horizontal refresh rates specified in the xorg.conf file (they should match your monitor specs).

I can't help with the ATI driver specifics, but others may do so.