Guys I Think finally fix it!
Last night I was thinking why glitch... why graphical issue when using some accelerated graphic... so the obvious... some of the clock steps are gone wrong... and then I decided to open with Kepler Bios Tweaker my BIOS and compare with other VGA we know work (in this case GTX670)... and Im look all the stuff and in the Voltage Tab I see some different
in VGA thats uses GK106 chipset... the Voltage table are set to be a range of voltages in P states... for example mine... it set to be 0.821 to 0.978 v... BUT in the GTX670 this settings are set IQUAL... in this case 0.978 - 0.978
Then I downloaded a GTX650Ti to look too... and my surprise... it have the same range voltage!
So what I did... rise this voltages to equal higher... save a new ROM of this BIOS... flashed with NVFlash.exe (you know what OS use this extension)... rebooted... and now I'm using the High Sierra an about 45min WITHOUT ANY GLITCH!
I will keep testing... and report later... but I'm testing the most common problems... Open and Close photos like a crazy... run a video on YouTube and changing sizes and full screen.. and NOTHING!
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EDIT... OK.. Glitches are back... BUT I noticed it stuck on 836mhz for GPU e 1.600mhz for DDR... so again I open the Kepler Bios Tweaker... and the P5 State of Clock I changed this values to the highest... and I miss 2 voltages on the Voltage Tab... so put all voltages the same and flashed again... so I'm testing... again
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EDIT again... Sorry guys... glitch everywhere
... sorry for the false rope