Sections
Categories
Useful Links
Tag CloudThe new function's simple name: Tessellation - one the most buzzy buzzwords about graphics technology in the past year and a half. It's function: Damage Control, or so you might think at the first glimpse at what it does. In it's current state in the recently leaked Catalyst 11.1a hotfix drivers, the function has two checkboxes and a slider. One of the checkboxes is called „AMD optimized” and the other is labelled „Use application settings”. The slider marked with „level” ranges from „Off” at the left to 64x at the rightmost position and controls the maximum tessellation factor to be employed by the graphics chips, which can be any of AMDs DirectX 11 series of Radeon HD cards.
Per driver default, Tessellation control is set to „AMD Optimized”, which, as Rage3d.com claims to be defined thus:
•The Catalyst Control Center includes an early prototype of some new tessellation controls. Our goal is to give users full control over the tessellation levels used in applications. The default selection „AMD Optimized” setting allows AMD, on a per application basis, to set the best level of tessellation. The intention is to help users get the maximum visual benefit of Tessellation, while minimizing the impact on performance. Currently no applications have been profiled, so the „AMD Optimized” setting will be non-operational until further notice.
•The „Use Application Settings” option gives applications full control over the Tessellation level. Users can also manually set the maximum tessellation level used by applications with the slider control.
•The long term goal for the „AMD Optimized” setting is to use the Catalyst Application Profile mechanism to control the AMD recommended level of tessellation on a per application basis. AMD’s intention is to set the tessellation level such that we will not be reducing image quality in any way that would negatively impact the gaming experience.
•The „Use Application Settings” option gives applications full control over the Tessellation level. Users can also manually set the maximum tessellation level used by applications with the slider control.
•The long term goal for the „AMD Optimized” setting is to use the Catalyst Application Profile mechanism to control the AMD recommended level of tessellation on a per application basis. AMD’s intention is to set the tessellation level such that we will not be reducing image quality in any way that would negatively impact the gaming experience.
Important to note
First, the described long term goal translates into nothing less than AMD overriding the developers choices as to how their applications have to look like. Let me be very clear about my opinion in this matter: This is something that should be left to the users' choices and no IHV is to touch.
The claim of not touching image quality in any way is the same made for their AI optimizations regarding texture filtering. More precise would be a description along the lines of not reducing image quality significantly, since any reduction of work done leads to a degradation in image quality. And that tradeoff should be made by the user and the user alone.
Second, the only problem I have with this new control, is AMD making it active by default. Contrary to what you might think after having read the above paragraphs, I really do like this control, as it is a means to improve user control over their applications. In a way it is the same as the slider for anisotropic filteirng: Let the application do it's thing by default, if you don't like it, you have the choice of limiting it's effect to a certain level. Very good. Especially for those applications tying all the DirectX 11 features into a single on/off switch.
Another potential danger are product reviews conducted by inexperienced reviewers who might not understand the feature correctly and use settings which are incomparable between competing products. Of course, this would not be what AMD had in my mind when designing this control!
Tessellation control explored
The switch is working, as I have confirmed on my Radeon HD 5870 running the leaked Catalyst 11.1a hotfix under Windows 7 x64. The driver default did nothing except to break Ozone3D.net's TessMark 0.2.2. completely - but that's more of a general issue with this driver - when I tried to get a nicely high result at the insane tessellation level (clamped to no tessellation at all via the driver). Both tessellation samples from Microsofts most recent DirectX SDK (June 2010) and from Nvidas GTX480 launch called Island11 were not limited in their tessellation functionality whatsoever and also the Unigine Heaven 2.1 Benchmark ran as it did always on my HD 5870.
There are some caveats using the Tessellation control, though. For example once you start to play around with the controls, you will find an option called
„Use application settings” - which sounds like it makes sense to use since you would expect it to use whatever the application decides. But beware: This setting works only as advertised as long as you drag the Level-slider below all the way to the right, to „64x”. If the slider is at any other position when you check „Use application setting”, it will only use a maximum of what the slider was set to, even though it appears to be at the 64x setting when greyed out. This way, I was able to „improve” my Unigine Heaven 2.1 score about 35% with extreme tessellation when in reality the Tessellation control kicked in and was limiting geometry amplification to 6x (the setting I left the slider in before clicking „Use application settings”).
In the pictures below, you can see how the clamped tessellation level is forced upon the respective application, ignoring their manually set tessellation factors
Conclusion
As outlined above, this control MUST not become active at driver default. The choice about the desired level of image quality is one each user must be able to make for himself. But as an option, this slider is something really adding value to AMDs Catalyst driver since it improves the users control over his or her machine and applications. Thus, I would welcome it to the official WHQL'ed Catalyst driver suite.
An official download will probably ready on january 26th, as indicated above. But there are a lot of links to various filehosters (use at your own risk!) and hardwareluxx.de seems to have the download including release notes at the ready also.
The hotfixes keep coming. After the Catalyst 11.1a hotfix has been leaked, so has it's update (note: do take anonymously uploaded files with a ton of salt and NEVER ever switch off your securities, only trust downloads from AMDs own servers!) which carries the filename „AMD_Catalyst_11.1a_Win7_Jan26.exe”. It seems, this is the one for January 26th to hit the hard drives as it already has been named accordingly.
It does indeed fix the broken Tessmark, but the tessellation controls do not work in this OpenGL benchmark from my friends at Ozone3D.net. Accordingly, the scores I get with my HD 5870 have not moved an inch from what I've posted before. In Unigine Heaven 2.1 however, they do work as noted above. With this new hotfix update, the Open GL render path from Unigine works way better than before and instead of totally crippling the score, framerate is only some ten to twentyish percent lower than under DirectX 11.
Speaking of which reminds me of another benchmark using both DirectX 11 and tessellation: 3DMark 11 (in case you cannot run it yourself, here's a youtube-clip). I was wondering if the new Catalyst's tessellation controls are working here too - and they are. With turning tessellation completely off, I was able to improve the graphics score by a whopping (no, not really) ~200 points from 4520 to 4713, the framerates in the graphics tests 2, 3 and 4 went up 2.3, 3.6 and 7.7 percent respectively. The first test stayed more or less the same, as it doesn't make use of tessellation, while the other three use increasing amounts of the geometry goodness by default. With this control in place, I am wondering how and if AMD will ever get an approval from Futuremark for their upcoming drivers.
Rate this article