Introduction

That’s right, we have the alpha version of mobility G-Sync up and running! See how variable refresh works without a G-Sync module!

It has been an abnormal week for us here at PC Perspective. Our typical review schedule has pretty much flown out the window, and the past seven days have been filled with learning, researching, retesting, and publishing. That might sound like the norm, but in these cases the process was initiated by tips from our readers. Last Saturday (24 Jan), a few things were brewing:

Ryan was informed by NVIDIA that the memory layout of the GTX 970 was different than expected.

The huge (now 168 page) overclock.net forum thread about the Samsung 840 EVO slowdown was once again gaining traction.

Someone got G-Sync working on a laptop integrated display.

We had to do a bit of triage here of course, as we can only research and write so quickly. Ryan worked the GTX 970 piece as it was the hottest item. I began a few days of research and testing on the 840 EVO slow down issue reappearing on some drives, and we kept tabs on that third thing, which at the time seemed really farfetched. With those two first items taken care of, Ryan shifted his efforts to GTX 970 SLI testing while I shifted my focus to finding out of there was any credence to this G-Sync laptop thing.

A few weeks ago, an ASUS Nordic Support rep inadvertently leaked an interim build of the NVIDIA driver. This was a mobile driver build (version 346.87) focused at their G751 line of laptops. One recipient of this driver link posted it to the ROG forum back on the 20th. A fellow by the name Gamenab, owning the same laptop cited in that thread, presumably stumbled across this driver, tried it out, and was more than likely greeted by this popup after the installation completed:

Now I know what you’re thinking, and it’s probably the same thing anyone would think. How on earth is this possible? To cut a long story short, while the link to the 346.87 driver was removed shortly after being posted to that forum, we managed to get our hands on a copy of it, installed it on the ASUS G751 that we had in for review, and wouldn’t you know it we were greeted by the same popup!

Ok, so it’s a popup, could it be a bug? We checked NVIDIA control panel and the options were consistent with that of a G-Sync connected system. We fired up the pendulum demo and watched the screen carefully, passing the machine around the office to be inspected by all. We then fired up some graphics benchmarks that were well suited to show off the technology (Unigine Heaven, Metro: Last Light, etc), and everything looked great – smooth steady pans with no juddering or tearing to be seen. Ken Addison, our Video Editor and jack of all trades, researched the panel type and found that it was likely capable of 100 Hz refresh. We quickly dug created a custom profile, hit apply, and our 75 Hz G-Sync laptop was instantly transformed into a 100 Hz G-Sync laptop!

Ryan's Note: I think it is important here to point out that we didn't just look at demos and benchmarks for this evaluation but actually looked at real-world gameplay situations. Playing through Metro: Last Light showed very smooth pans and rotation, Assassin's Creed played smoothly as well and flying through Unigine Heaven manually was a great experience. Crysis 3, Battlefield 4, etc. This was NOT just a couple of demos that we ran through – the variable refresh portion of this mobile G-Sync enabled panel was working and working very well.

At this point in our tinkering, we had no idea how or why this was working, but there was no doubt that we were getting a similar experience as we have seen with G-Sync panels. As I digested what was going on, I thought surely this can’t be as good as it seems to be… Let’s find out, shall we?