Barts & tessellation rate, please explain

[chavvdarrr]

How important (or not so) is tesselation rate factor?
Is the limited "bonus" in tesselation for Barts good enough, or its still DX11 not-done-right from the eyes of developer?

 

[Davros]

bonus ?

 

[Psycho]

We don't really know what's optimized yet, and which bottleneck it fixes.

 

[chavvdarrr]

Well, we have

http://home.akku.tv/~akku38901/HD6/5.jpg

 

[no-X]

Damiens test is interesting...

HD5870 vs. HD6870, tesselation:

no culling: +44%
low culling: +44%
high culling: +46%
tess. + DM: +46%
ad. tess. + DM: +11%
tess. ultra + DM: +31%
ad. tess. ultra + DM: +55%

http://www.hardware.fr/articles/804-7/dossier-amd-radeon-hd-6870-6850.html

 

[fellix]

So, Barts goes to 1/2 tessellated throughput up from 1/3 in Evergreen...

 

[DarthShader]

How important (or not so) is tesselation rate factor?
Is the limited "bonus" in tesselation for Barts good enough, or its still DX11 not-done-right from the eyes of developer?

Our second tessellation test is Microsoft’s DirectX 11 Detail Tessellation sample program, which is a much more straightforward test of tessellation performance. Here we’re simply looking at the framerate of the program at different tessellation levels, specifically level 7 (the default level) and level 11 (the maximum level). Here AMD’s tessellation improvements become even more apparent, with the 6870 handily beating the 5870. In fact our results are very close to AMD’s own internal results – at level 7 the 6870 is 43% faster than the 5870, while at level 11 that improvement drops to 29% as the increased level leads to an increasingly large tessellation factor. However this also highlights the fact that AMD’s tessellation performance still collapses at high factors compared to NVIDIA’s GPUs, making it all the more important for AMD to encourage developers to use more reasonable tessellation factors.

So I guess the answer would be: it's important.

Btw. Found a HAWX2 benchamrk tested:
http://www.hardware.fr/articles/804-17/dossier-amd-radeon-hd-6870-6850.html

Matches an extreme tess setting, doesn't it? But why tessellate ground so much?

 

[Malo]

What is the difference between them without Tessellation? Is there any way to decrease the Tessellation in that benchmark?

 

[Davros]

Matches an extreme tess setting, doesn't it? But why tessellate ground so much?

From Amd

"It has come to our attention that you may have received an early build of a benchmark based on the upcoming Ubisoft title H.A.W.X. 2. I'm sure you are fully aware that the timing of this benchmark is not coincidental and is an attempt by our competitor to negatively influence your reviews of the AMD Radeon™ HD 6800 series products. We suggest you do not use this benchmark at present as it has known issues with its implementation of DirectX® 11 tessellation and does not serve as a useful indicator of performance for the AMD Radeon™ HD 6800 series. A quick comparison of the performance data in H.A.W.X. 2, with tessellation on, and that of other games/benchmarks will demonstrate how unrepresentative H.A.W.X. 2 performance is of real world performance.

AMD has demonstrated to Ubisoft tessellation performance improvements that benefit all GPUs, but the developer has chosen not to implement them in the preview benchmark. For that reason, we are working on a driver-based solution in time for the final release of the game that improves performance without sacrificing image quality. In the meantime we recommend you hold off using the benchmark as it will not provide a useful measure of performance relative to other DirectX® 11 games using tessellation."

 

[Xenus]

No offense to AMD but that sounds like we are worse in the way they are using Tessellation so we will just force our way in drivers kinda like the whole FP11 vs FP16 thing all over again. We can argue the merits of the way HAWX 2 is doing it vs the way AMD wants it done all day but I don't like driver enhancements like this from either side.

 

[no-X]

Even HD5830 performs around 60 FPS at 1920*1200 +AA4x...

What is the the big thing, which was worth the marketing/PR comedy? The additional 100 FPS over HD5000, which are discarded by 60Hz LCD? Desperate try...

 

[DarthShader]

From Amd

I read that. I am wondering about the practical aspect though, not technical.

I tried to transalte the page from Damien, worked good enough to read, that adaptive tessellation is apparently not in use. So distant miniature triangles will get processed over and over. Ok, I can see the potential of improving the way those traingles would appear on the screen when we get closer, it would be fluid. How about including a switch in the options, for enabling/disabling adaptive tess?

What is the the big thing, which was worth the marketing/PR comedy? The additional 100 FPS over HD5000, which are discarded by 60Hz LCD? Desperate try...

This is a flight simulator. Simulators are a genre, that probably benefits the most from a multimonitor setups. See the issue now?

 

[Sontin]

I read that. I am wondering about the practical aspect though, not technical.

I tried to transalte the page from Damien, worked good enough to read, that adaptive tessellation is apparently not in use. So distant miniature triangles will get processed over and over. Ok, I can see the potential of improving the way those traingles would appear on the screen when we get closer, it would be fluid. How about including a switch in the options, for enabling/disabling adaptive tess?

You can download the benchmark from here: http://www.nzone.com/object/nzone_hawx2_downloads.html

Check it out. You will see that ubisoft is using adaptive tessellation.
And then, maybe you find the water demo from nvidia. They implemented a dynamic lod setting. But the problem with the adaptive tessellation is that a morphing world is ridicolous. And with a open terrain like in HAWX you can't do it to aggressive.

 

[3dcgi]

So, Barts goes to 1/2 tessellated throughput up from 1/3 in Evergreen...

And how efficient is Nvidia hardware? A 460 has twice the theoretical rate.

I think there is some confusion as to what adaptive tessellation means. It's a very generic term. People seem to think it refers to distance based tessellation, but another layer is view angle based. Parts of objects viewed straight on need less tessellation that silhouettes. I don't know what HAWX 2 is doing, but I hope they've at least implemented distance based adaptive tessellation.

Edit: in another thread Sontin linked a presentation describing the tessellation algorithm.

 

[stevem]

And how efficient is Nvidia hardware? A 460 has twice the theoretical rate.

It may be the case that only the Quadro variants are capable of theoretical rate.

 

[AlexV]

It may be the case that only the Quadro variants are capable of theoretical rate.

No.

 

[no-X]

This is a flight simulator. Simulators are a genre, that probably benefits the most from a multimonitor setups. See the issue now?

Which is pretty poor by nVidia, cause you need 2 GeForce cards for 3 LCDs. If you buy 2 Radeons instead, performance will be sufficient for 3 LCDs. No real advantage for GeForce user, again.

 

[CarstenS]

Even HD5830 performs around 60 FPS at 1920*1200 +AA4x...

What is the the big thing, which was worth the marketing/PR comedy? The additional 100 FPS over HD5000, which are discarded by 60Hz LCD? Desperate try...

AMD seems to think differently. Or why else would they have issued the cited statement if it didn't seem somehow important to them?

 

[no-X]

Yes, 60 FPS isn't enough for AMD's marketing department, if the competitor offers 180 FPS. But 60 FPS clearly is sufficient for gaming.

 

[GZ007]

Isnt the fermi also doing something similar like quad fragment merging for shading.
http://graphics.stanford.edu/papers/fragmerging/shade_sig10.pdf
Wouldnt the paralel rasterization go into vain if u would waste so much time on shading even on fermi cards.