Interesting article in Pc Perspective by Ryan Shrout:
link:
http://www.pcper.com/reviews/Graphics-C ... DIA-G-Sync
During an impromptu meeting with AMD this week, the company's Corporate Vice President for Visual Computing, Raja Koduri, presented me with an interesting demonstration of a technology that allowed the refresh rate of a display on a Toshiba notebook to perfectly match with the render rate of the game demo being shown.
All that is needed for this to work, as AMD explained it, was an eDP connection between the discrete GPU and the display, a controller for the screen that understands the variable refresh rate methods of eDP 1.0 specifications and an updated AMD driver to properly send it the signals. The panel can communicate that it supports this variable refresh technology to the graphics card through the EDID as resolutions and timings are communicated today and then the graphics driver would know to send the varying vblank signals to adjust panel refresh times on the fly.
But here is where it might get interesting: the upcoming DisplayPort 1.3 standard actually includes the same variable refresh rate specification. That means that upcoming DP 1.3 panels COULD support variable refresh technology in an identical way to what we saw demoed with the Toshiba laptops today. DP 1.3 is on schedule to be ratified as a standard in the next 60-90 days and from there we'll have some unknown wait time before we begin to see monitors using DP 1.3 technology in them.
AMD is hopeful it will happen in Q3 of 2014 but speed of integration has never been a highlight of the DisplayPort standard.
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.
And another one by Scott Wasson from The Tech Report:
link:
http://techreport.com/news/25878/nvidia ... -sync-demo
On the show floor here at CES today, I spoke briefly with Nvidia's Tom Petersen, the executive instrumental in the development of G-Sync technology, about the AMD "free sync" demo we reported on yesterday.
Petersen quickly pointed out an important detail about AMD's "free sync" demo: it was conducted on laptop systems. Laptops, he explained, have a different display architecture than desktops, with a more direct interface between the GPU and the LCD panel, generally based on standards like LVDS or eDP (embedded DisplayPort). Desktop monitors use other interfaces, like HDMI and DisplayPort, and typically have a scaler chip situated in the path between the GPU and the panel. As a result, a feature like variable refresh is nearly impossible to implement on a desktop monitor as things now stand.
That, Petersen explained, is why Nvidia decided to create its G-Sync module, which replaces the scaler ASIC with logic of Nvidia's own creation. To his knowledge, no scaler ASIC with variable refresh capability exists—and if it did, he said, "we would know."
When asked about a potential VESA standard to enable dynamic refresh rates, Petersen had something very interesting to say: he doesn't think it's necessary, because DisplayPort already supports "everything required" for dynamic refresh rates via the extension of the vblank interval. That's why, he noted, G-Sync works with existing cables without the need for any new standards. Nvidia sees no need and has no plans to approach VESA about a new standard for G-Sync-style functionality—because it already exists.