The AMD FreeSync Review
by Jarred Walton on March 19, 2015 12:00 PM ESTFreeSync Features
In many ways FreeSync and G-SYNC are comparable. Both refresh the display as soon as a new frame is available, at least within their normal range of refresh rates. There are differences in how this is accomplished, however.
G-SYNC uses a proprietary module that replaces the normal scaler hardware in a display. Besides cost factors, this means that any company looking to make a G-SYNC display has to buy that module from NVIDIA. Of course the reason NVIDIA went with a proprietary module was because adaptive sync didn’t exist when they started working on G-SYNC, so they had to create their own protocol. Basically, the G-SYNC module controls all the regular core features of the display like the OSD, but it’s not as full featured as a “normal” scaler.
In contrast, as part of the DisplayPort 1.2a standard, Adaptive Sync (which is what AMD uses to enable FreeSync) will likely become part of many future displays. The major scaler companies (Realtek, Novatek, and MStar) have all announced support for Adaptive Sync, and it appears most of the changes required to support the standard could be accomplished via firmware updates. That means even if a display vendor doesn’t have a vested interest in making a FreeSync branded display, we could see future displays that still work with FreeSync.
Having FreeSync integrated into most scalers has other benefits as well. All the normal OSD controls are available, and the displays can support multiple inputs – though FreeSync of course requires the use of DisplayPort as Adaptive Sync doesn’t work with DVI, HDMI, or VGA (DSUB). AMD mentions in one of their slides that G-SYNC also lacks support for audio input over DisplayPort, and there’s mention of color processing as well, though this is somewhat misleading. NVIDIA's G-SYNC module supports color LUTs (Look Up Tables), but they don't support multiple color options like the "Warm, Cool, Movie, User, etc." modes that many displays have; NVIDIA states that the focus is on properly producing sRGB content, and so far the G-SYNC displays we've looked at have done quite well in this regard. We’ll look at the “Performance Penalty” aspect as well on the next page.
One other feature that differentiates FreeSync from G-SYNC is how things are handled when the frame rate is outside of the dynamic refresh range. With G-SYNC enabled, the system will behave as though VSYNC is enabled when frame rates are either above or below the dynamic range; NVIDIA's goal was to have no tearing, ever. That means if you drop below 30FPS, you can get the stutter associated with VSYNC while going above 60Hz/144Hz (depending on the display) is not possible – the frame rate is capped. Admittedly, neither situation is a huge problem, but AMD provides an alternative with FreeSync.
Instead of always behaving as though VSYNC is on, FreeSync can revert to either VSYNC off or VSYNC on behavior if your frame rates are too high/low. With VSYNC off, you could still get image tearing but at higher frame rates there would be a reduction in input latency. Again, this isn't necessarily a big flaw with G-SYNC – and I’d assume NVIDIA could probably rework the drivers to change the behavior if needed – but having choice is never a bad thing.
There’s another aspect to consider with FreeSync that might be interesting: as an open standard, it could potentially find its way into notebooks sooner than G-SYNC. We have yet to see any shipping G-SYNC enabled laptops, and it’s unlikely most notebooks manufacturers would be willing to pay $200 or even $100 extra to get a G-SYNC module into a notebook, and there's the question of power requirements. Then again, earlier this year there was an inadvertent leak of some alpha drivers that allowed G-SYNC to function on the ASUS G751j notebook without a G-SYNC module, so it’s clear NVIDIA is investigating other options.
While NVIDIA may do G-SYNC without a module for notebooks, there are still other questions. With many notebooks using a form of dynamic switchable graphics (Optimus and Enduro), support for Adaptive Sync by the Intel processor graphics could certainly help. NVIDIA might work with Intel to make G-SYNC work (though it’s worth pointing out that the ASUS G751 doesn’t support Optimus so it’s not a problem with that notebook), and AMD might be able to convince Intel to adopt DP Adaptive Sync, but to date neither has happened. There’s no clear direction yet but there’s definitely a market for adaptive refresh in laptops, as many are unable to reach 60+ FPS at high quality settings.
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Midwayman - Thursday, March 19, 2015 - link
If you have a display with backlight strobing (newest light boost, benq blur reduction, etc) the difference is readily apparent. Motion clarity is way way way better than with out. The issue is its like a CRT and strobbing is annoy at low rates. 75hz is about the absolutely min, but 90hz and above are better. I doubt any of the displays support strobing and adaptive sync at the same time currently, but when you can push the frames, its totally worth it. The new BenQ mentioned in the article will do both for example (Maybe not at the same time.) That way you can have adaptive sync for games with low FPS and strobing for games with high fps.darkfalz - Thursday, March 19, 2015 - link
Games at 100+ FPS look much smoother. Think of it like perfect motion blur. If you can keep your game between 72-144 Hz it's gaming nirvana.eddman - Thursday, March 19, 2015 - link
I'm not a fan of closed, expensive solutions, but this hate towards g-sync that some here are showing is unwarranted.nvidia created g-sync at a time where no other alternative existed, so they created it themselves, and it works. No one was/is forced to buy it.
It was the only option and those who had a bit too much money or simply wanted the best no matter what, bought it. It was a niche market and nvidia knew it.
IMO, their mistake was to make it a closed, proprietary solution.
Those consumers who were patient can now enjoy a cheaper and, in certain aspects, better alternative.
Now that DP adaptive-sync exists, nvidia will surly drop the g-sync hardware and introduce a DP compatible software g-sync. I don't see anyone buying a hardware g-sync monitor anymore.
Murloc - Thursday, March 19, 2015 - link
you don't understand the hate because you think nvidia will drop g-sync immediately.It's likely you're right but it's not a given.
Maybe it will be a while before the market forces nvidia to support adaptive sync.
MikeMurphy - Thursday, March 19, 2015 - link
nVidia will protect manufacturers that invested resources into G-Sync. They will continue support for G-Sync and later introduce added support for Freesync.ddarko - Thursday, March 19, 2015 - link
The fact that only AMD cards work with Freesync now is not because Freesync is closed but because Nvidia refuses to support it. It takes a perverse kind of Alice in Wonderland logic to use the refusal of certain company to support an open standard in its hardware as proof that the open standard is in fact "closed."Freesync is open because it is part of the "open" Displayport standard and any display and GPU maker can take advantage of it by supporting that relevant Displayport standard (because use of the Displayport standard that Freesync is part of is free). Nvidia's Gsync is "closed" because Nvidia decides who and on what terms gets to support it.
Whatever the respective technical merits of Freesync and Gsync, please stop the trying to muddy the water with sophistry about open and closed. Nvidia GPU can work with Freesync monitors tomorrow if Nvidia wanted it - enabling Freesync support Nvidia a dime of licensing fees or requirement the permission of AMD or anyone else. The fact that they choose not to support it is irrelevant to the definition of Displayport 1.2a (of which Freesync is a part of) as an open standard.
mrcaffeinex - Thursday, March 19, 2015 - link
Are NVIDIA's partners able to modify their cards BIOS and/or provide customized drivers to support FreeSync or do they have to rely on NVIDIA to adopt the feature? I know different manufacturers have made custom cards in the past with different port layouts and such. I never investigated to see if they required a custom driver from the manufacturer, though. Is it possible that this could be an obstacle that an EVGA, ASUS, MSI, etc. could overcome on their own?JarredWalton - Thursday, March 19, 2015 - link
It would at the very least require driver level modifications, which the card manufacturers wouldn't be able to provide.chizow - Thursday, March 19, 2015 - link
How is this even remotely a fact when AMD themselves have said Nvidia can't support FreeSync, and even many of AMD's own cards in relevant generations can't support it? Certainly Nvidia has said they have no intention of supporting it, but there's also the possibility AMD is right and Nvidia can't support it.So in the end, you have two effectively closed and proprietary systems, one designed by AMD, one designed by Nvidia.
iniudan - Thursday, March 19, 2015 - link
Nvidia cannot use FreeSync as it is AMD implementation of VESA's Adaptive Sync, they have to come up with their own implementation of the specification.