Transparency AA, Purevideo, and HDTV

On of the problems with Multisample AA is its inability to correct aliasing within a polygon. One of the main new features that NVIDIA added to the G70 is a method to combat the most notorious problem associated with MSAA: antialiasing of transparent textures.

When transparency AA is enabled on a GeForce 7800 GTX, textures that make use of the alpha channel can be flagged to have either supersample or multisample AA performed inside the texture. This can help a great deal for features often implemented with transparent textures such as leaves, vegetation or chain link fences.

This affords an increased performance hit along with its higher image quality, but no longer will fences, bushes, and trees cause a marked decrease in image quality even while running 4xAA. We will explore the performance hit and quality of Transparency AA in our analysis of the hardware, but NVIDIA provides the option of running with either SSAA or MSAA in this mode. MSAA incurs less of a performance hit, but SSAA is higher quality. We are glad that the choice is left to the end user and would even prefer that we get the choice in how FSAA is performed as well.

With increasingly powerful hardware we can afford to "waste" some cycles on SS in order to achieve slightly higher image quality in game that are severely CPU bound. Check out our recent Insider Article on NVIDIA's upcoming introduction of a 16x AA mode for 7800 GTX SLI systems. We will test this mode as soon as NVIDIA offers a driver with support for it.

This time around, Purevideo has extended support for HD format acceleration. The 7800 GTX will now have support for spatial-temporal de-interlacing for HD content. This feature promises to make 1080i content look that much better on a PC. NVIDIA has also said that the 7800 GTX should support H.264, but have said that the driver will not have support until near year's end. As we have already seen an H.264 demo from ATI, and the lack of anything tangible from NVIDIA at this point is disappointing. We are hesitant to even mention NVIDIA's claimed "support" before we see it running on actual hardware (especially after the lacking and late Purevideo support for initial NV40 parts). This time around, we can expect more support for alternate video players from NVIDIA as they are working with InterVideo and Cyberlink.

Not tied to the 7800 GTX is NVIDIA's latest improvement on HDTV support in their 75 series drivers (also launching today). Over time support for fitting a PC's output to any HDTV has improved, but this latest update makes it that much easier to deal with. Providing sliders and a full screen underscan adjustment feature is long overdue, but we still wish modern hardware could provide a more fully featured plug and play environment for HDTV.

We will also be getting some Windows MCE extensions that make HDTV setups easier to configure as well. If the US can manage to keep broadcast flags off the law books, public support for and adoption of digital television services and computers as media center boxes will surely continue to grow and prosper.

No More Shader Replacement The Test, Card, and High Resolution
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  • BenSkywalker - Wednesday, June 22, 2005 - link

    Derek-

    I wanted to offer my utmost thanks for the inclusion of 2048x1536 numbers. As one of the fairly sizeable group of owners of a 2070/2141 these numbers are enormously appreciated. As everyone can see 1600x1200x4x16 really doesn't give you an idea of what high resolution performance will be like. As far as the benches getting a bit messed up- it happens. You moved quickly to rectify the situation and all is well now. Thanks again for taking the time to show us how these parts perform at real high end settings.
  • blckgrffn - Wednesday, June 22, 2005 - link

    You're forgiven, by me anyway :) It is also the great editorial staff that makes Anandtech my homepage on every browser on all of my boxes!

    Nat
  • yacoub - Wednesday, June 22, 2005 - link

    #72 - Totally agree. Some Rome: Total War benchs are much needed - but primarily to see how the game's battle performance with large numbers of troops varies between AMD and Intel more so than NVidia and ATi, considering the game is highly CPU-limited currently in my understanding.
  • DerekWilson - Wednesday, June 22, 2005 - link

    Hi everyone,

    Thank you for your comments and feedback.

    I would like to personally apologize for the issues that we had with our benchmarks today. It wasn't just one link in the chain that caused the problems we had, but there were many factors that lead to the results we had here today.

    For those who would like an explanation of what happened to cause certain benchmark numbers not to reflect reality, we offer you the following. Some of our SLI testing was done forcing multi-GPU rendering on for tests where there was no profile. In these cases, the default mutli-GPU mode caused a performance hit rather than the increase we are used to seeing. The issue was especially bad in Guild Wars and the SLI numbers have been removed from offending graphs. Also, on one or two titles our ATI display settings were improperly configured. Our windows monitor properties, ATI "Display" tab properties, and refresh rate override settings were mismatched. This caused the card to render. Rather than push the display at a the pixel clock we expected, ATI defaulted to a "safe" mode where the game is run at the resolution requested, but only part of the display is output to the screen. This resulted in abnormally high numbers in some cases at resolutions above 1600x1200.

    For those of you who don't care about why the numbers ran the way they did, please understand we are NOT trying to hide behind our explanation as an excuse.

    We agree completely that the more important issue is not why bad numbers popped up, but that bad numbers made it into a live article. For this I can only offer my sincerest of apologies. We consider it our utmost responsibility to produce quality work on which people may rely with confidence.

    I am proud that our readership demands a quality above and beyond the norm, and I hope that that never changes. Everything in our power will be done to assure that events like this will not happen again.

    Again, I do apologize for the erroneous benchmark results that went live this morning. And thank you for requiring that we maintain the utmost integrity.

    Thanks,
    Derek Wilson
    Senior CPU & Graphics Editor
    AnandTech.com
  • Dmitheon - Wednesday, June 22, 2005 - link

    I have to say, while I'm am extremely pleased with nVidia doing a real launch, the product leaves me scratching my head. They priced themselves into an extremely small market, and effectively made their 6800 series the second tier performance cards without really dropping the price on them. I'm not going to get one, but I do wonder how this will affect the company's bottom line.
  • OrSin - Wednesday, June 22, 2005 - link

    I not tring to be a buthole but can we get a benchmark thats a RTS game. I see 10+ games benchmarks and most are FPS, the few that are not might as well be. Those RPG seems to use a silimar type engine.
  • stmok - Wednesday, June 22, 2005 - link

    To CtK's question : Nope, SLI doesn't work with dual-display. (Last I checked, Nvidia got 2D working, but NO 3D)...Rumours say its a driver issue, and Nvidia is working on it.

    I don't know any more than that. I think I'd rather wait until Nvidia are actually demonstrating SLI with dual or more displays, before I lay down any money.
  • yacoub - Wednesday, June 22, 2005 - link

    #60 - it's already to the point where it's turning people off to PC gaming, thus damaging the company's own market of buyers. It's just going to move more people to consoles, because even though PC games are often better games and much more customizable and editable, that only means so much and the trade-off versus price to play starts to become too imbalanced to ignore.
  • jojo4u - Wednesday, June 22, 2005 - link

    What was regarding the AF setting? I understand that it was set to 8x when AA was set to 4x?
  • Rand - Wednesday, June 22, 2005 - link

    I have to say I'm rather disappointed in the quality of the article. A number of apparently nonsensical benchmark results, with little to no analysis of most of the results.

    A complete lack of any low level theoretical performance results, no attempts to measure any improvements in efficiency of what may have caused such improvements.

    Temporal AA is only tested on one game with image quality examined in only one scene. Given how dramatically different games and genres utilize alpha textures your providing us with an awfully limited perspective of it's impact.

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