![]() The cost of implementing 4x MFAA is a hair higher than 2x MSAA because the temporal synthesis filter has some computational overhead. The end result is a coverage pattern that is identical to 4x MSAA but uses only two samples per pixel (aka 2x MSAA) to achieve it. Reiterating the crux, what's really happening here is that MFAA is approximating 4x MSAA by using two samples, located in two different sub-pixel areas, on two consecutive frames. Nvidia is still achieving four subsamples per pixel, but it is using two subsamples over two frames instead of four over one. The final task is in combining the average colour outputs of the two frames by using a temporal synthesis filter and then displaying the twin-frame result on screen. Changing the coverage points influences the average colour, albeit on two different frames. It is this change of location that is important. In the subsequent frame n, the location-programmable MFAA subsamples are rotated to cover two different points. In frame n-1 two MFAA subsamples cover each of the four pixels surrounding the edge. MFAA's trick is to use just two coverage subsamples but produce the same kind of result as having four samples. Having programmable location is the first part. In a 4x4 grid of a pixel, MFAA can choose between 16 different locations. The key is the programmable nature of sub-pixel sampling, as the MFAA algorithms can place the sub-pixels - the red and green dots in the above picture - at various locations. MFAA works by using multi-pixel programmable sampling. Nvidia's MFAA aims to provide 4x MSAA-like image quality at the cost of 2x MSAA. The more subpixel samples taken the better, leading to alias-free edges, but MSAA remains expensive in terms of memory-bandwidth usage and ROP utilisation. This is why MSAA does a good job of making edges look smoother - the at-edge pixel is coloured properly to avoid the staircase effect of harsh colour transitions. Average colour information from these subpixels is downsampled using a filter and presented on-screen. 2x MSAA takes two samples while 4x MSAA grabs four samples per pixel. The current pre-stored standard, Multi-Sample AA (MSAA), uses a technique that tests for edges (coverage) and determines the average colour at that point by taking a number of subsamples of the pixel straddling the edge. Understanding MFAA requires knowledge of how the underlying AA technology is used to improve visual quality by reducing jaggies present in standard-resolution frames. Switching gears, Nvidia is also introducing a new antialiasing method known as Multi-Frame AA (MFAA). There's no need to go all the way up to 4K internal rendering Nvidia provides a bunch of intermediate DSF factors. This isn't wholly new technology, mind, as hacks have been in place that force the GPU to render to a higher internal resolution and downsample to match what is outputted, but the use of poor filters has limited the appeal of such an approach.ĭSR is built into GeForce Experience, or can be set manually in the control panel. Nvidia sees it a different way, where burning fps isn't a problem if you have a surfeit to begin with. Rendering at 4K, as you will see in performance benchmarks, can reduce framerate by up to 75 per cent, plus a little overhead for the Gaussian filter. The obvious downside to DSR is that internal rendering at a higher resolution beats up on framerate. There are no more pixels when compared to an image of the same resolution, but visuals are a touch better. Perhaps the technology can be best imagined as rescaling a 4K photograph down to 1080p through the use of an efficient, high-quality filter. Dynamic Super Resolution (DSR)Īnswering the question of visual quality on easy-to-render games first, Nvidia is debuting a technology called Dynamic Super Resolution (DSR). So how does one increase visual fidelity and/or speed it's bit of a conundrum, isn't it? Nvidia is also introducing a couple of new software-based techniques to make games look better and run faster on GeForce hardware, particularly for users with 1080p monitors. Now, as much as we eulogise about gaming on high-resolution monitors - 4K, anyone? - the majority of users still run with 1,920x1,080 (1080p) screens. In an ideal world you'd want to improve the IQ of games that run quickly natively, so they look as good as possible, while also being able to increase the speed of graphically-taxing games without diminishing that lovely IQ. ![]() ![]() On the other hand, graphically-intensive games such as Battlefield 4 and Crysis 3 run slowly when image quality settings are set to high or ultra-high. ![]() Older or well-coded games such as Dark Souls II and Grid Autosport run just fine on high-end graphics cards, often rendering at an average 100fps at a 1080p resolution. Improving Image Quality And Speed: DSR and MFAA ![]()
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