Custom Resolution Utility (CRU)

[Marsh]

Hi guys, I'm curious if you could troubleshoot what issues I've come upon with my graphics card or just ensure me that what I'm trying to do is not possible.
I have an ASUS R7250-1GD5 card that has a single-link DVI-D slot. I currently have a 144hz monitor running 60hz through the DVI cable it came with.
From what I've done I'm conflicted on whether I could ever reach a higher refresh rate or whether I'll just need to upgrade it. I'm lead to believe I can still find a work around with help.
I've patched the pixel clock and without even having to use the CRU at all I can select the 100,120,144hz options that were previously not there but with trouble. One being that 144hz is not compatible whatsoever which I was not necessarily worried about because 120hz worked alright. Given that my monitor itself will prompt an "incorrect cable" error and repeatably do so when you exit it with the monitor button. BTW I'm trying to figure this out to play CS:GO on so that error message on my monitor in itself is the biggest problem because I can choose 120hz with the pixel clock patched and change it on my CS and achieve the refresh rate I'd desire but cannot actually commit to playing because of the pop-up.
Lastly if the above can be solved I'm curious what I would need to use within CRU to achieve maximum performance. I haven't consistently played the game at 120hz enough with the error message to determine if there are any true stutters or freezes or whatever you would to call it while overclocked or if its my GFX itself. BTW my GFX itself runs well enough that I can achieve 150+ frames consistently to run the desired refresh rates.
I'm very curious if you have any solutions or if I can now just upgrade my system given your information, thanks so much guys.