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Anti-Aliasing Analysis, Part 2: Performance

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November 21, 2011 4:25:03 AM

This series is one of the best. The first article was most illuminating, and the second keeps it coming. Before the first article I was clueless to nVidia's AA nomenclature. Now it makes much more sense, and I applaud nVidia for not making the situation worse (though nVidia and AMD need nomenclature help in other areas still).

I'm not a huge gamer and the games I do play mostly run awesome with my 2500K + GTX460. I decided that if it's going to be a while before the next generation of GPUs drop, I'd get another 460. So that's what I did, should be here in a few days. I was worried that even at 1920x1200 I'd have problems with AA and the lack of VRAM, but it's good to see that two 460s work pretty admirably.

As an aside, I'm totally on an efficiency kick, and I don't relish the thought of needing two cards to get decent performance, but the GTX 460 is one of the most efficient cards around well over a year after it's release.
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November 21, 2011 9:17:25 AM

What happened to Morphological AA? When the 6000 series was released, Morph AA showed an impressively low demand on hardware - about 2 or 3 fps lost -, and now it's cutting frame rates in half?

Seriously, what is it?
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November 21, 2011 10:06:28 AM

Great article! Very ilustrating!
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Anonymous
November 21, 2011 11:25:22 AM

This article is going to have me diving into my settings tonight, I've basically set my aged 5770 to run as poorly as possible given I game at 1920x1200 :/  Learn something new every day ;) 
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November 21, 2011 11:51:17 AM

ZehWhat happened to Morphological AA? When the 6000 series was released, Morph AA showed an impressively low demand on hardware - about 2 or 3 fps lost -, and now it's cutting frame rates in half?


Was thinking the same thing....part 1 and part 2 are contradicting each other hear...if i'm remembering part 1 correctly...

btw there's a typo at the start of page 2,
Quote:
This is because the GT 420 is not DirectX 11-capable
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November 21, 2011 12:42:26 PM

ZehWhat happened to Morphological AA? When the 6000 series was released, Morph AA showed an impressively low demand on hardware - about 2 or 3 fps lost -, and now it's cutting frame rates in half?Seriously, what is it?


On release we tested StarCraft II because that was a game that choked with MSAA on Radeons. It turns out, that game is severely CPU limited, so it wasn't the best test subject for Morphological AA
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November 21, 2011 12:50:23 PM

I don't like these animated gifs for comparing anti-aliasing modes, because 1. gifs are limited to 256 colors, 2. moving around in a game will affect how noticeable the differences in quality between different anti-aliasing modes are. (so will the physical size of the pixels, but that would probably be impractical to represent when viewed on other monitors). Would it be possible to get some animations that show antialiasing modes side-by-side (or half and half) while moving around in some of these games, instead of just fixed-position images that cycle between anti-aliasing modes?
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November 21, 2011 2:32:36 PM

MauveCloudI don't like these animated gifs for comparing anti-aliasing modes, because 1. gifs are limited to 256 colors, 2. moving around in a game will affect how noticeable the differences in quality between different anti-aliasing modes are.


As for #2, there's no worries as the Half Life 2 engine in Lost Coast that we used for the majority of comparison shots doesn't move the camera during idle times. We used a save game and reloaded the scene at exactly the same position, so its not an issue here.

As for your first concern, I was worried about that, too, at first. But I carefully scrutinize the uncompressed TIFF files before exporting them to GIF and in these cases there's no practical difference, it does an excellent job of demonstrating the result with different AA modes.
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November 21, 2011 2:35:06 PM

Very interesting article! Although I'm a tad confused by your nomeclature of the Radeon AA settings. There's MSAA, AMSAA, SSAA, and within those you can choose box, narrow tent, wide tent, and edge detect types (edge being the only one AFAIK to increase demand), and then on top of that you can enable Morphological. So, I'm not sure what "EQ" means as it is not at all a term used by Radeon (or at least CCC).

Also, as the first poster said, why is morphological so demanding all of a sudden? When I first tried using it, I barely saw an impact on performance and in a couple games it made everything look blurry. I just tried enabling it in Skyrim (a game that really needs better AA) and my performance plummeted - which these results confirm. What changed?
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November 21, 2011 2:44:10 PM

wolfram23 So, I'm not sure what "EQ" means as it is not at all a term used by Radeon (or at least CCC).


As it says in the article, EQAA is Radeon HD 6900-series exclusive. You probably don't have a 6900 card.

wolfram23Also, as the first poster said, why is morphological so demanding all of a sudden?


The answer is 5 posts above this comment. :)  Depends on the game, you may have been using a CPU-bottlenecked title.
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Anonymous
November 21, 2011 2:47:35 PM

I wish for a DX10 card, they would have thrown in a card a lot of us probably have/had, like a GTX260.
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November 21, 2011 4:12:37 PM

I must say the animated GIFs are pro status....I wanna see a giant GIF with all modes compared....like a gradual no AA to MAX aa...I know there are tons of modes but that is just the "jist" of the idea.
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November 21, 2011 4:41:35 PM

mt2eI must say the animated GIFs are pro status....I wanna see a giant GIF with all modes compared....like a gradual no AA to MAX aa...I know there are tons of modes but that is just the "jist" of the idea.


Check our AA Analysis Part 1 article, lots more comparisons there:

http://www.tomshardware.com/reviews/anti-aliasing-nvidi...

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November 21, 2011 5:54:20 PM

Great article.

FYI, typo in first paragraph, "the image quality the impart" (should be "they")
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November 21, 2011 6:28:32 PM

Also, if you download NVidia inspector, you can use Sparse Grid SS Transparency AA (doesn't work in all games). Looks better than regular Transparency SS AA but even more demanding. It is not available in the normal control panel.
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November 21, 2011 7:14:38 PM

Interesting, but the 450px × 448px images are too small for me to see the differences well.
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November 21, 2011 7:45:32 PM

CleeveAs for #2, there's no worries as the Half Life 2 engine in Lost Coast that we used for the majority of comparison shots doesn't move the camera during idle times. We used a save game and reloaded the scene at exactly the same position, so its not an issue here.


You misunderstand my concern here. I'm not talking about whether the screenshots are in the same position. I'm talking about users actually moving around in the game (it's not common when actually playing any of these games to stay in one place for long, right?) and whether the qualitative differences between antialiasing modes are still as noticeable while moving.
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November 21, 2011 8:45:28 PM

MauveCloud whether the qualitative differences between antialiasing modes are still as noticeable while moving.


Ah. Well for that you should try it out. in my experience the stills represent what happens in-game quite well, except when it comes to post processing effects like Morphological and FXAA. Those tend to crawl because the filer re-assesses each frame independently, it's not based on the same geometric data like MSAA.
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November 21, 2011 8:46:04 PM

DXRickInteresting, but the 450px × 448px images are too small for me to see the differences well.


It's 1 to 1, so if you can't see a difference there, you won't see it in game.
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November 21, 2011 8:48:07 PM

pdxoutdoorsGreat article.FYI, typo in first paragraph, "the image quality the impart" (should be "they")


Thx, fixed!
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November 21, 2011 9:32:17 PM

cleeve said:
As it says in the article, EQAA is Radeon HD 6900-series exclusive. You probably don't have a 6900 card.



The answer is 5 posts above this comment. :)  Depends on the game, you may have been using a CPU-bottlenecked title.


Thanks for replying!

You're right I'm not on a 6900 card so I guess that takes care of that :) 

The (recent) game I just tried to use morphological on was Skyrim. I've read that it's CPU intensive and yet my i5 750 at 4ghz is barely being utilized, like at best 50%. People have said it is a CPU intensive game, yet plenty of games use much more of my CPU like BF3 and Crysis 2, among others. At the same time, I've heard that it is really only using 2 threads, in which case I suppose it would make sense that I see 50% usage on a quad core. I don't know if that is true or not.
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November 22, 2011 12:03:23 AM

On page 2 there is a typo that calls a GT 240 a GT 420
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November 22, 2011 2:37:53 AM

wolfram23I've read that it's CPU intensive and yet my i5 750 at 4ghz is barely being utilized, like at best 50%. People have said it is a CPU intensive game


Well, Skyrim might be better described as CPU-*dependent*, not intensive. It doesn't appear to use more than 2 threads, at least it didn't in our Skyrim performance analysis. Having said that, frame rate was very dependent on the CPU at the Ultra setting, but this dependance was really minimized if you use High or lower settings.

It's the Ultra setting that kills Skyrim and really shifts the bottleneck to the CPU.
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November 22, 2011 2:43:43 AM

zepfan_75 said:
On page 2 there is a typo that calls a GT 240 a GT 420


Doh! fixed.

Dyslexics Are Teople Poo.
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Anonymous
November 22, 2011 5:35:18 AM

Nice article (both the current '2nd' and the 1st AA-Analysis), its an excellent write up.

---

If the article is to educate users about viable Anti Aliasing modes and types present on their drivers/games which can be utilized, it could be better if the following could be included.

.It would also be a nice touch if there are screen shots (as mentioned by some earlier) at the same time-stamps across the same AA_modes and but different AA_Types for the same resolution for different games, ideally at the highest playable resolution achievable on single GPU cards.

On the lines like; 8xMSAA, 16xCSAA, 8xEQAA, 24xEDAA, 8xMSAA+Transparency, 4xMLAA...all@1920x1080.

.Also expanding the article to cover a games which have more detailed geometry and varied texture images on geometry could help.

.If possible there could be an AA image repository where an article could be linked, while bumping it up for every new game which is bench-marked.

my cent
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November 22, 2011 6:29:38 AM

"The highest-quality AA mode, supersampling essentially renders the frame at a higher resolution and downsamples the result. This causes a performance hit so large that Nvidia straight-up removed this mode from its GeForce drivers some time ago."

Under "Antialiasing - Transparency" , the options show "Multisample" then "2x, 4x, and 8x(Supersample)". Are these really just higher levels of Multisampling and not actual Supersampling? I assume that's the case.

;) 
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Anonymous
November 22, 2011 7:44:34 AM

"Supersampling is the granddaddy of all anti-aliasing modes. For all intents and purposes, this method essentially renders the output at a higher resolution and down-samples (averages out) the result."


@Author, Please double confirm if this is how it works on AMD drivers.

Because AMD's method of 'SSAA' (Sparse Rotated Grid) option doesn't appear to work by upscaling the whole image and then downscale the same as a final result, the technique in AMD's implementation appears to be different.

Instead of traditional SSAA, AMD's technique appears to involve taking duplicate copies of the frame/image, then taking sampling values across these images with the duplicate frame/images themselves as per the defined spaced and rotated grid pattern.

This is one of the main reasons when AMD's SSAA is not possible in all games (DirectX 9), AMD's SSAA fails if the game itself cannot support AMD's basic MSAA in the first place.
(ie..AMD's SSAA only works if AMD's MSAA works in that specific game in the first place)


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November 22, 2011 9:53:52 AM

I would love to see higher resolutions being the norm, with upscale to normal resolutions if graphics can't keep up. Like 4k2k resolution on a 21' display. If 2560x1600 can be made into a tablet size, why can't desktop computers grow to 4k2k or even 8k4k. No need to see all the individual pixels. They would be naturally merged together, instead of AA merged. And with the proper performance hit, which would be a good excuse for more graphics power, they could be rendered without the upscale. Else, a render of 1080p could be upscaled with precise 2x ratio to a 4k2k display, without visual artifacts and performance hit.
I am a fan of higher resolutions :) 
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November 22, 2011 12:18:27 PM

Marcus52 said:

Under "Antialiasing - Transparency" , the options show "Multisample" then "2x, 4x, and 8x(Supersample)". Are these really just higher levels of Multisampling and not actual Supersampling? I assume that's the case.


Transparency AA isn't full-scene AA like MSAA or AMD's SSAA.

Nvidia's transparency AA works ONLY on transparent textures, not on the entire frame.

If you turn on Transparency supersampling, all of the edges of geometry will remain aliased. Nvidia removed FSAA supersampling from their drivers long ago. ;) 
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November 22, 2011 12:35:20 PM

Quote:
"Supersampling is the granddaddy of all anti-aliasing modes. For all intents and purposes, this method essentially renders the output at a higher resolution and down-samples (averages out) the result."


@Author, Please double confirm if this is how it works on AMD drivers.

Because AMD's method of 'SSAA' (Sparse Rotated Grid) option doesn't appear to work by upscaling the whole image and then downscale the same as a final result, the technique in AMD's implementation appears to be different.

Instead of traditional SSAA, AMD's technique appears to involve taking duplicate copies of the frame/image, then taking sampling values across these images with the duplicate frame/images themselves as per the defined spaced and rotated grid pattern.


That analogy is simply for the purpose of teaching, it's not meant as a literal description of how a graphics card creates a supersampling result (although it's an excellent description of what's happening).

Having said that, that analogy applies just as well to sparse rotated grid. Sparse rotated grid still samples more than once per pixel to down-sample the result, the difference being that it doesn't use an ordered grid to sample the pixel (it doesn't sample every single position in the grid), and the grid is rotated to provide better anti-aliasing on lines close to vertical and horizontal.

All versions of AA can be described as downsampling actually, because they take more than one sample per pixel and average out the result. But SSAA fits this description best as it works on every pixel in the scene, and each pixel is fully sampled more than once (regardless of the rotation of the grid or whether or not each position in the grid is sampled).
MSAA only takes extra samples for pixels on the edge of geometry, and when it does apply AA to a pixel that pixel is not fully sampled (only depth and stencil values are fully sampled, some things such as pixel shaders are only sampled once per pixel).
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November 22, 2011 10:22:04 PM

Fabulous article btw. Addressing video quality in terms other than frame rate is something hardware sites tend to stay away from - and that's easy enough to understand, since it becomes extremely difficult to attach hard numbers to what you see on a screen. Even frame rate statistics don't tell you what you actually see in a game. Thanks for stepping up and helping educate us, and demonstrating the differences between graphics card technologies for those of us who can't do side-by-side comparisons.

;) 
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November 24, 2011 6:25:35 AM

CleeveIt's the Ultra setting that kills Skyrim and really shifts the bottleneck to the CPU.


Are you sure? I run the game on ultra @1980, and I haven't seen any sort of performance issue despite running at stock cpu speeds currently (due to my memory at post being less than it should be, troubleshooting)
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November 24, 2011 5:12:59 PM

neiroatopelccAre you sure? I run the game on ultra @1980, and I haven't seen any sort of performance issue despite running at stock cpu speeds currently (due to my memory at post being less than it should be, troubleshooting)


Absolutely sure! Check the benchmarks:

http://www.tomshardware.com/reviews/skyrim-performance-...

If you think the results are off, you're welcome to duplicate the benchmark procedure and test it yourself... I'd be interested in seeing if your results are significantly different.
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November 25, 2011 9:01:21 AM

if I have time I might. But my schedule's full of boxes with stuff that isn't home :( 
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November 28, 2011 5:30:37 AM

Great Artical, very informative.
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November 30, 2011 10:15:51 PM

Zeh said:
What happened to Morphological AA? When the 6000 series was released, Morph AA showed an impressively low demand on hardware - about 2 or 3 fps lost -, and now it's cutting frame rates in half?

Seriously, what is it?


They tested MLAA with MSAA enabled as well, which is not the intended functionality. It's meant to be used by itself.
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November 30, 2011 10:17:47 PM

From the article:

Quote:
Supersampling is the granddaddy of all anti-aliasing modes. For all intents and purposes, this method essentially renders the output at a higher resolution and down-samples (averages out) the result.


This isn't how the Radeon 5000/6000 series SSAA works. What it does is apply the same sampling technique as MSAA but for every pixel in the scene.

It wouldn't even be possible for the Radeon implementation to render at a higher resolution and downsample because their SSAA uses a rotated grid, not ordered.
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