Overclocking a dell u2414h help please

[gamer]

Hello,

I've recently got the dell u2414h and I've heard of others overclocking the monitor to 80hz, as well as the lower tier model, the p2414h that apparently uses a near identical panel.

I've tried using the following timings from the overclock.net forum

Quote:Use displayport connection.
In windows 8.1:
Press Win + R and type: CustomModeApp
Set accordingly:
Horizontal Active: 1920
Horizontal Front Porch: 30
Horizontal Sync Width: 40
Horizontal Back Porch: 45
Horizontal Total: 2035
Horizontal Sync: +

Vertical Active: 1080
Vertical Front Porch: 3
Vertical Sync Width: 4
Vertical Back Porch: 5
Vertical Total: 1092
Vertical Sync: +

80Hz no frame skipping

These timings don't seem to work for me and I get an out of range error, but I don't have access to Displayport. I've tried with my HDMI cable from the monitor that goes to a mini-hdmi port on my GPU.

Would HDMI essentially be the same procedure at displayport, or is some type of hdmi limitation holding me back compared to displayport? Would the timings be different for different connections types between HDMI and Displayport?

I've tried using CRU for this and left it at manual, but as I mentioned, it doesn't work. I've managed to get it up to 74hz doing nothing but changing the refresh rate in CRU with manual timings at default.

Any help would be greatly appreciated.