AMD's ATI Radeon HD 5870 Video Card Review
AMD’s ATI Radeon HD 5800 series debuts today and the new ATI Radeon HD 5870 is now available. We will give you all the gritty details of the HD 5800 Series, and show you just how well the new flagship ATI Radeon HD 5870 accelerates games. Can you say, “I like twice as much performance in the same power envelope.”
Filtering Image Quality
Let’s start right off the bat looking at filtering quality since ATI has put a lot of effort into making it "perfect" with the 5800 series.
The first screenshot above shows all three video cards being tested here today with Trilinear filtering, i.e. no Anisotropic filtering, their default settings. What will catch your eyes immediately is the fact that the Radeon HD 5870 exhibits a perfect circle on all filtering levels as we look down the tunnel. The GeForce GTX 285 seems to be better than the Radeon HD 4890, so the HD 5870 is a big improvement over AMD’s previous generation.
In the second screenshot we have enabled 16X AF. Once again we find the Radeon HD 5870 produces the best 16X AF out of the bunch. It is a perfect circle, with no dependencies on angles like the Radeon HD 4890. I would say ATI has succeeded in providing the absolute best filtering quality in a gaming graphics card.
Antialiasing Image Quality
The first thing we wanted to look at is to see if the sample patterns have changed from the HD 4890 to the HD 5870.
In the above screenshot we are looking at the Geometry sample patterns at 8X MSAA on all three video cards. We notice that there are no changes in the patterns between the HD 4890 and HD 5870. The GTX 285 at 8xQ AA is only slightly different in its arrangement. ATI has had the sample patterns positioned well in their previous generation for 2X, 4X and 8X AA.
Now, in the above screenshot we wanted to compare 2X AA, 4X AA and 8X AA in a game. We are using Ghostbusters which with new drivers allows us to enable AA from the control panel for each video card. In the first screenshot you can see what this scene looks like at 1920x1200 with No AA, it is quite aliased.
As you look across 2X AA, 4X AA and 8X AA comparisons here we are very hard pressed to see any differences in AA image quality. The Radeon HD 5870 matches the previous generation HD 4890 quite well. The GTX 285 using true MSAA modes also matches quite well with the HD 4890 and HD 5870. In our gaming, we did not notice any difference in image quality at 2X, 4X and 8X MSAA settings between all three video cards.
Since the Radeon HD 5870 supports Supersampling we had to look at performance and image quality with this new option. By the way, Supersampling AA does work across ALL AA modes on the HD 5870. It will work in combination with all CFAA modes using Edge Detect.
Supersampling AA definitely works in reducing aliasing, on all textures, polygons and even eliminates shader aliasing. However, as you can see above in all three screenshot comparisons, enabling Supersampling AA also causes a reduction in texture quality. By enabling even the lowest 2X Supersampling AA we found that textures started to look blurry, losing their detail and crispness. This, unfortunately, is the nature of Supersampling AA. It literally is a full screen AA method that eliminates jaggies on EVERYTHING, but at the same time degrades texture quality.
Therefore, this AA setting will have to be used at your own discretion, and we think it will have limited use in most games. It degrades image quality, and it is a burden on the GPU, a big one. However, there may be some applications or older games, where this could be of benefit. Some games, such as Ghostbusters, suffer from heavy shader aliasing, and Supersampling AA will eliminate this. At least AMD is giving us the option to use it or not. Supersampling AA is a feature of the Radeon HD 5800 series only, and will not be supported on previous generation video cards.