Can display 1920x1080p @ 60Hz, but can only display 75Hz @ 1152x864?

[trogdor8freebird]

My computer monitor normally displays 1920x1080p @ 60 Hz. Recently I looked at the AMD Catalyst Control Center and in the flat-panel properties the maximum reported refresh rate it says 75 Hz. So, I tried to change the refresh rate and when I did it set me to 1152x864 resolution. If I change the resolution to 1920x1080 the refresh rate changes to 60 Hz.

Is this a bug, or is that somehow intended?

Specs"

Monitor: I think it's this, though I'm uncertain.
CPU: Phenom II x6 1045t
RAM: 8GB 1333
GPU: Radeon 6950 2GB

 

[manofchalk]

Basically, there is only so much bandwidth available in the cable between your PC and monitor, and with the exception of Dual Link DVI and DisplayPort, 1080p 60hz is the most you can put through these cables. If you want a higher refresh rate, it has to sacrifice resolution so it still fits in with the bandwidth limitations.
If you are using Dual Link DVI and this is happening, then more than likely the other end of the connector (internal to the monitor) just doesn't support those extra pins, or the monitor is changing the settings so it doesn't exceed rated spec.

Completely intended.
Besides, theres a very good chance your monitor cannot physically display a refresh rate above 60hz anyway.