Blur Busters Forums

Per the PC Perspective article:

Finally, as a last minute stirring of the pot, I received an email from AMD's Koduri that indicated that there might be some monitors already on the market that could support variable refresh rate TODAY with just a firmware update. This would be possible if a display was shipping with a controller that happened to coincidentally support variable refresh, perhaps in an early stage of development for the upcoming DP 1.3 standard. We are trying to find a list of these monitors so we can talk with them and ask for these necessary changes.

http://www.pcper.com/reviews/Graphics-C ... DIA-G-Sync

Assuming we have a new enough monitor that already supports variable refresh rates (possibly with the need of a firmware update), does this mean nVIDIA and AMD could both enable "FreeSync" now at the driver level?

Personally, I cannot wait to see this list of monitors that currently support variable refresh rates!

I hope nVIDIA decides to support both Variable Refresh Rate (aka FreeSync) and G-SYNC in their drivers!

nVidia doesn't believe that any monitors on the market currently support variable refresh rate and based on the hardware they had to design to make it work, I'm doubting it as well. Keep in mind that the FreeSync demo was done on a laptop, which is designed much differently from a desktop display. AMD also stated that their focus for the technology was on mobile device power savings, rather than gaming.

Basically, I'll believe it when I see it.

nimbulan wrote:nVidia doesn't believe that any monitors on the market currently support variable refresh rate

I think there's some truth to both sides:

1. AMD Side -- I think the key distinction is laptop LCD controllers that already automatically slow down the refresh rate to save power. I have had a Lenovo ThinkPad at one of my former jobs, and that's what it did. It seems FreeSync is hijacking that as a method of eliminating stutters/tearing. It makes sense, provided the controllers are flexible enough to let that be done.

2. NVIDIA Side -- I think NVIDIA needed the custom FPGA to flawlessly pull off what they needed on modern 120Hz & 144Hz panels. Flawless, flickerfree, operation of variable refresh rate over a wide refresh rate range (30Hz through 144Hz) is far more difficult than variable refresh rate over a small range (e.g. 40Hz-60Hz). You've got the massive bandwidth of full HD resolution going 144 cycles a second -- a far cry from laptop LCD.

Some unanswered questions:
-- Wondering how realtime variable the AMD implementation of VRR is. Every single frame? Just a few times a second?
-- Wondering what the refresh rate range the AMD implementation of VRR is. 30 through 60Hz?

You need single-frame granularity for true VRR. GSYNC is single-frame granular; which means NVIDIA can change refresh rate over a hundred times a second -- every single frame. If AMD is a slowly-slewing version or creates artifacts (e.g. even the faintest noticeable flicker during fast refresh rate changes, can be annoying), then it will not be as good as NVIDIA's. However, even if it is a problem now, I don't see any reason why future manufacturing of LCDs can solve this issue, for better embedded/included FreeSync/GSYNC implementations without needing a FPGA.

More monitor makers and HDTV makers need to pay attention to this now. We need to put Freesync/GSYNC in televisions too...

Chief Blur Buster wrote: Some unanswered questions:
-- Wondering how realtime variable the AMD implementation of VRR is. Every single frame? Just a few times a second?
-- Wondering what the refresh rate range the AMD implementation of VRR is. 30 through 60Hz?

Hmm is it possible that freesync is in essence framerate limiter that sends information to monitor to adjust refresh rate accordingly ?

If it's done in small enough granularity with proper frequency it could work ?

So the effect would be similar to vsync but instead of dropping from 60 to 30 fps we would see drop from 60 to 57 for example.