After that i received a notification on my laptop status taskbar, that G-Sync is enabled and the display refreshment were changed to 75Hz (it shows, that you do not need the extra physical chip, to set your older model to G-Sync).
I have installed only moded Nvidia Geforce driver from some guy called GAMENAB, without new Bios flash or something (driver only). So, i decided to check if my laptop is G-Sync capable.
It has Full HD display with 60Hz refreshment, GTX980M 4GB, I7 4710HQ. Youtube from Gamenab's blog: (I did not get to copy this data before it was too late) Atm his site is still up, but nvidia is taking it down: (download the html file and open it in a browser) So even if Asus wanted to give their customers support for gsync on current models, nvidia would not allow them. This is backed up with Asus relasing a new model of the g751 that have the same panel and gpu, just with gsync enabled. Nvidia will probably not allow laptops that are allready sold to be certified as gsync capable. The laptop producers such as Asus have to pay a premium price to get gsync support on their laptops. It looks like the current owners of the g751 have been test subjects for the certification process of that panel. What would be the reason for this? Well it looks like nvidia had a large scale test to see if the panel could handle the refresh rates for a longer period. The current g751 laptops also had their refresh rate increased to 75hz and then down again to 60hz with a driver.
Nvidia has stopped his work, and they will sue anyone that tried to give the current g751 models gsync. He has also worked on a modified bios version for the gpus on the current models that will give us the same gsync as the "gsync" model. Ive also tested gsync on my own model, and apart from black frames on lower framrates it works fine. A person calling himself Gamenab has allready relased a gsync driver that works with the older models, just with a few beta bugs. Asus claims that the old g751 does not support gsync, and you have to buy the new G751 Gsync model to get this feature. The computer if fully capable of gsync, but nvidia wont allow it. Short answer: No, there will be no support for gsync on the current g751 models.