BenQ XL2730Z - What is required for smooth 1440p @ 120Hz?

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I had the XL2411Z and just upgraded to this monitor as I wanted something larger and with a higher resolution. I have an AMD R9 280 which is unfortunately not free-sync enabled, so guess what is on my Christmas list, however my questions are related to MBR as compared to the XL2411Z I am finding it difficult to find a configuration I think looks reasonable/as good. This is over a Dual Link DVI connection.

I have used the CRU to create a custom resolution of 2560x1440 @ 120Hz. I have not adjusted the vertical/horizontal totals yet as I am worried about the clock speed. At present the pixel clock speed is at 480.40 MHz (naturally I had to use the AMD Clock Patcher to go over 300MHz).

I wish to ask:
1) I notice that when I use the custom resolution, my MBR menu in the OSD has two new options: Intensity & Area. What are these?
2) Is the pixel clock being at 480.40 MHz safe? It feels rather high compared to what the value was for the XL2411Z - naturally that was 1080p, but still I just wish to make sure I am not doing something crazy.
3) Is overclocking the monitor like this likely to cause damage to it, or is it more the GPU I should be concerned about?

When I say that the MBR experience thus far has not been on par with the XL2411Z, I mean in terms of the ghosting I can see, and I get an occasional stutter which may be FPS related, I'm unsure. Any advice and information appreciated, thanks!