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First AMD FreeSync Capable Gaming Displays and Drivers Launched, Tested
MojoKid writes Soon after NVIDIA unveiled its G-SYNC technology, AMD announced that it would pursue an open standard, dubbed FreeSync, leveraging technologies already available in the DisplayPort specification to offer adaptive refresh rates to users of some discrete Radeon GPUs and AMD APUs. AMD's goal with FreeSync was to introduce a technology that offered similar end-user benefits to NVIDIA's G-SYNC, that didn't require monitor manufacturers to employ any proprietary add-ons, and that could be adopted by any GPU maker. Today, AMD released its first FreeSync capable set of drivers and this first look at the sleek ultra-widescreen LG 34UM67 showcases some of the benefits, based on an IPS panel with a native resolution of 2560x1080 and a max refresh rate of 75Hz. To fully appreciate how adaptive refresh rate technologies work, it's best to experience them in person. In short, the GPU scans a frame out to the monitor where it's drawn on-screen and the monitor doesn't update until a frame is done drawing. As soon as a frame is done, the monitor will update again as quickly as it can with the next frame, in lockstep with the GPU. This completely eliminates tearing and jitter issues that are common in PC gaming. Technologies like NVIDIA G-SYNC and AMD FreeSync aren't a panacea for all of PC gaming anomalies, but they do ultimately enhance the experience and are worthwhile upgrades in image quality and less eye strain.
Vsync keeps a frame from being written to the monitor until the monitor is ready for it. Say for example, your card can generate 70 FPS and your display is clocked at 60 FPS, your card will draw a frame, wait for the end of the previous frame, send the newest frame, then start generating the next frame. You lose out on the extra 10 fps that your card could be producing. On the other hand, if you run up against a heavy scene and your card's capability drops to 59 fps, it will take more than a single refresh to draw a frame, so your card re-sends the last frame while it waits for the current frame to finish, finishes the current frame, then sits around waiting for the re-sent frame to finish drawing. You eliminate tearing, but effectively drop to 30 fps. If your engine works a bit different and starts drawing the next frame ahead of time instead of waiting, you get jitters where several frames draw smoothly but eventually catch up with the buffer and stutter while a frame is skipped.
Gsync, on the other hand, moves the waiting to the monitor side. A frame is drawn to the monitor as soon as it is complete. If you're producing frames faster than the max refresh rate, your card might still stop and wait while the frame is being sent, but if your framerate drops, you don't end up in a buffer-skip cycle. Instead of sending every frame by the clock, the card sends the frames as they finish, and the monitor doesn't refresh until it receives the full frame, regardless of whether it produces the full 60 FPS or a lower rate. This wouldn't work well with a CRT since every line has to be refreshed every cycle to maintain constant brightness and minimize flicker, but it works well with flat panel displays where each element is updated simultaneously only when the refresh signal is sent.