X-bit labs

News Glance: The Essential Commentary on the Week’s Hottest News (page 5)

Category: Editorial

by Anton Shilov

[ 06/14/2004 | 08:04 AM ]

NVIDIA and ATI Fight for Better Trilinear Filtering Quality

The wars for the best image quality in 3D games continued this week when our colleagues from ComputerBase.de web-site published a report concerning a possibility to disable ATI’s optimizations of trilinear filtering from the registry.

Graphics competition these days is more connected with performance numbers for the majority of buyers rather than with image quality for 3D graphics gurus. As a consequence, we should probably expect loads of trick, tweaks and cheats from variety of IHVs in order to pump the speed up.

Getting something of better quality is always a nice option, but with the common approach to simplify everything for the sake of speed it is very questionable whether we should pay attention to the quality of trilinear filtering or we should sacrifice it for higher performance. Or maybe hardware developers should let end-users to decide whether she or he needs the optimizations or not from the driver’s control panel?

Painkiller performance with and without filtering optimizations.

“Disabling the trilinear optimization will not enable users to choose between performance and quality.  Everyone on the web has been absolutely clear: there is no image quality degradation with this optimization. Therefore, a control panel option would not change image quality, only performance. We do not anticipate adding a checkbox to disable the optimization to future control panels. What would we label it?  “Reduce performance”?  “Lower frame rates”? Because that is all that switching off the trilinear optimization would do,” commented Chris Evenden for ATI Technologies.

Luciano Alibrandi, European PR Manager at NVIDIA Corp., was more laconic: “Wait few hours… I believe tomorrow morning you will have the response you are waiting for.”

The next morning X-bit labs got a new version of NVIDIA’s soon-to-be-released ForceWare drivers that allowed to turn on and off all filtering optimizations, including trilinear optimization and anisotropic optimization, even though, by default both types of simplifications were enabled.

“If you want to compare red and green performance, please make sure not to compare “full trilinear” with “almost bilinear” (“red driver default”). No matter if someone telling you “patent pending”. In the early nineties, in connection with Winbench, some “driver optimizations” even exceeded the physical memory bandwidth. And even those optimizations have been presented as advantages for the customers,” said Hans-Wolfram Tismer, Gainward’s Managing Director in Europe, who is pretty well-known for making wrong accusations Futuremark’s patches of having negative effect on NVIDIA’s ForceWare shader compiler.

“Modern computer games use extremely complex techniques that are hard to compute in the real-time. In fact, the whole 3D graphics on personal computers is a kind of approximation since it is impossible to get desirable performance amid breath-taking image quality in case we simplify nothing. Therefore, game developers are supposed to approximate certain calculations – including pixel shaders, filtering, etc – in order to make them work quicker and attain high numbers of frames per second. Nowadays games use astonishingly detailed terrains with loads of polygons that do not allow us to see where the full-trilinear filtering and where is the simplified trilinear filtering is,” said Andrew Filimonov, an independent graphics and design expert from Estonia and the developer of Xbitmark benchmark.

Painkiller performance with and without filtering optimizations.

“Since the latest controversy hit the web, numerous graphics hobbyists out there have been looking for evidence of image quality degradation. They have found nothing. So I really believe that there are no image quality problems with this [trilinear filtering] optimization. Remember when “optimization” meant “make something better”?  This is one of those optimizations, like back in the good old days before the 3DMark03 got compromised,” continued Chris Evenden, ATI Technologies’ Public Relations Director.

“Contemporary graphics cards, such as the NVIDIA GeForce 6800 Ultra and the ATI RADEON X800 XT are so powerful that they hardly require additional performance boosters that degrade image quality. However, for competition reasons both leading developers of graphics products decided to implement optimizations in order to add performance to their new products. Simplifications of trilinear and anisotropic filtering, partial precision of pixel shaders calculations, application specific optimizations, you name it, without letting customers to enable “premier image quality” are the examples of pretty unfair behavior of IHVs. Fortunately, NVIDIA decided to let the customers decide whether they need simplifications of trilinear and anisotropic filtering or not. This is an advantage for the ForceWare, as ATI’s CATALYST drivers still lack this feature,” said Alexey Stepin, a graphics analyst at X-bit labs.

One more problem with allowing customers to disable optimizations is that few end-users have enough qualification to tweak their graphics cards to achieve optimal ration between speed and stability. In case we turn off trilinear, anisotropic filtering optimizations and then disable pixel shader optimizations in FarCry game, we are likely to get slide-show performance even on $499 NVIDIA GeForce 6800 UIltra. Customers will not like low FPS, at the same time, the majority would not see any difference – ATI’s X800 optimizations have been around in the RADEON 9600 for over a year and no one noticed them – between simplified and non-simplified trilinear filtering.

NVIDIA allows its customers to tweak graphics cards according to preferences. ATI does not. Which approach is the right one is something that only time will tell.