NVidia 7900 Can't Render AA & HDR at once!?

[ELGoku]

Sup Guys, I was checking the Nvidia vs ATI slugfest on gamespot just now, and it turns out that the 7900 can't perform with the AA & HDR at the same time!? how can this be!? What I also want to know if It's the same in the 7800 Series?

Here's the article.
GameSpot ATI vs Nvidia Slugfest

 

[cleeve]

Yep, all of Nvidia's SM 3.0 cards have the limitation... from the 6x00 series to the 7x00 series.

Just the OpenEXR method of HDR though. Half Life 2 uses a different method.

 

[nottheking]

Sup Guys, I was checking the Nvidia vs ATI slugfest on gamespot just now, and it turns out that the 7900 can't perform with the AA & HDR at the same time!? how can this be!? What I also want to know if It's the same in the 7800 Series?

Here's the article.
GameSpot ATI vs Nvidia Slugfest

That comes as no surprise, given that all in all, the G71 (GF7900) is a REFRESH of the G70. (GF7800) Pretty much, it's just a re-design to both increase power by a decent bit, and drastically reduce production costs. No new features.

However, to say that it can't do AA and HDR at the same time is a lie; it only cannot do MULTI-SAMPLE AA, along with OpenEXR HDR, at the same time; use super-sampling, or some other method, and it works fine. This includes the latest nVidia tech demos, which DO use AA and HDR. (note that the HDR in Oblivion, at least the SM 3.0 components, also cannot be used with multi-sample AA on any card, including Radeon X1ks, given that the developers disabled it)

Want to use HDR and AA on a GeForce 6 or 7? (if you have one, that is) Check out RTHDRIBL. It also uses SM 2.0, so it can even be used on GeForce FX 5xxx cards as well. Of course, not that you'd WANT to use it on said cards, given the rather hefty performance cost the thing has.

 

[cyph0r]

Wait Wait WAit Set me straight. i have Dual 7900 GTX. I want to run HDR and AA. what is and is not possible cause there seems to be some confusion here (card settings would be helpfull)

 

[delanooch]

Anisotropic filtering can be turned on all he way which helps a bit, so is this a driver issue? no HDR and AA? I have heard this before but never really got too worried about it since most of the games I play right now dont use HDR. but I have already invested in 2 - 7800GTX's so I guess I don't really care is it does it or not.

 

[cleeve]

It's not a driver issue, it's a hardware limitation.

Plain and simple, there will be some games that AA & HDR can't be used at the same time on 6x00 and 7x00 hardware.

Far Cry and it's HDR patch are one example. You can do AA & HDR on the ATi 1Xx00 cards, but not the Nvidia 6x00/7x00 cards. It'll either refuse to do it, or crash.

 

[nottheking]

Wait Wait WAit Set me straight. i have Dual 7900 GTX. I want to run HDR and AA. what is and is not possible cause there seems to be some confusion here (card settings would be helpfull)

Well, if you want to use "standard" AA with a game using OpenEXR for it's HDR, which includes popular HDR-enabled games like Far Cry, Splinter Cell 3, and the like, then it's impossible with your cards; such can currently only be done with a Radeon X1300, X1400, X1600, X1800, or X1900 card.

However, you can use other forms of AA, such as super-sampling, or "SLi AA," which are both done post-processing, and hence will work no problem. Also, with other types of AA, such as that used in the RTHDRIBL demo mentionmed above, and those used in nVidia's GeForce 6 and 7 tech demos, will work fine with normal "multi-sample" AA.

 

[cyph0r]

It's not a driver issue, it's a hardware limitation.

Plain and simple, there will be some games that AA & HDR can't be used at the same time on 6x00 and 7x00 hardware.

Far Cry and it's HDR patch are one example. You can do AA & HDR on the ATi 1Xx00 cards, but not the Nvidia 6x00/7x00 cards.

so no matter what settings i put on the card i cant use HDR + AA??

 

[cyph0r]

Wait Wait WAit Set me straight. i have Dual 7900 GTX. I want to run HDR and AA. what is and is not possible cause there seems to be some confusion here (card settings would be helpfull)

Well, if you want to use "standard" AA with a game using OpenEXR for it's HDR, which includes popular HDR-enabled games like Far Cry, Splinter Cell 3, and the like, then it's impossible with your cards; such can currently only be done with a Radeon X1300, X1400, X1600, X1800, or X1900 card.

However, you can use other forms of AA, such as super-sampling, or "SLi AA," which are both done post-processing, and hence will work no problem. Also, with other types of AA, such as that used in the RTHDRIBL demo mentionmed above, and those used in nVidia's GeForce 6 and 7 tech demos, will work fine with normal "multi-sample" AA.

so your saying "SLi AA," + HDR is possible?

 

[delanooch]

try it , you have nothing to lose

 

[tenaciousleydead]

so you just have to change a driver settings? cause i was gonna buy a 7900GT soon and do want to play games in all their glory. and does the post proccessing Super-AA effect the performance alot? Thank You.

 

[pauldh]

SSAA takes such a performance hit it isn't even going to be possible to use in the latest games on a single 7900 series card. I saw numbers in some review where SSAA had like half the performance of MSAA. It's way less efficient. So unless it's an older game or you are happy at a low resolution, forget SSAA and therfore AA and HDR(such as in farcry, SCCT,etc.) at the same time with a GF7 card. Safer bet for AA and HDR is the X1900XT or X1800XT on a budget.

 

[pauldh]

and does the post proccessing Super-AA effect the performance alot?

Yep, big time. I'll post links if I can dig them up.

 

[cyph0r]

what about dual 7900 GTX in SLi-AA and HDR will that work?

 

[pauldh]

I don't know to be honest. I thought SLI 16X AA was just MSAA an SSAA combined, which I'd think would still have limitations with the method of HDR used in games like Farcry and SCCT. As far as power, I know dual 7900GTX can run 4X Transparency SSAA at 16x12 in Doom3, which single cards don't have the power to do. That was in a [H] review that they found that playable. BUT, TR SSAA is not real SSAA from my understanding, which admittedly is not that great. But Dave B. at B3D said that in the forums. If I can dig up his MSAA and SSAA explanation in my history, I will post it. it was a good one.

In times like this when the technicals go above my knowledge, I say, Grape? where are you?

 

[pauldh]

I can't find one case of either SSAA or SLI-AA working along with HDR in Farcry, SPCT, or SS2, with a GF6 or GF7. If it works, which it very well could, lets see some Farcry screenshots and performance figures for dual 7900GTX. Why hasn't anyone tried it. I don't care if it's 5fps, I just would like to see a valid case of both working together. I'd think with ATI being able to do MSAA and HDR in farcry, someone with dual 7800GTX of 7900GTX would have tried to get some method of AA and HDR to work. All I see is examples and testimonials where MSAA and HDR don't work together on NV cards. Anyway, i am done searching on this.

 

[cyph0r]

I can't find one case of either SSAA or SLI-AA working along with HDR in Farcry, SPCT, or SS2, with a GF6 or GF7. If it works, which it very well could, lets see some Farcry screenshots and performance figures for dual 7900GTX. Why hasn't anyone tried it. I don't care if it's 5fps, I just would like to see a valid case of both working together. I'd think with ATI being able to do MSAA and HDR in farcry, someone with dual 7800GTX of 7900GTX would have tried to get some method of AA and HDR to work. All I see is examples and testimonials where MSAA and HDR don't work together on NV cards. Anyway, i am done searching on this.

once my proc gets delivered ill give it a shot and post some Screenies and some Benchmarks.

 

[cleeve]

I did the same search myself.

All I find is the odd claim that only supersampling is limited, but no-one has ever produced a screenie of an OpenEXR game working with AA on an Nvidia card.

Someone supplied a screenie of AOE3 working with AA & HDR once, but the AOE3 devs specifically made a non-OpenEXR path for that to work, so it reverts to a non-OpenEXR path on Nvidia cards when AA is enabled...

 

[TheGreatGrapeApe]

I did the same search myself.

All I find is the odd claim that only supersampling is limited, but no-one has ever produced a screenie of an OpenEXR game working with AA on an Nvidia card.

That's just it. We've discussed this before and no one, not a reviewer, not even people at B3D has ever been able to explain that statement. I think some of it may come from the fact that nV mentiones MSAA and not SSAA, but no one explained how the limitation would work since the only one I've heard sofar is that nV's HDR implementation (use of OpenEXR spec) used in conjunction with MSAA runs out of memory (needs some ridiculous numbers like 2+GB), but why would that be true for MSAA and not SSAA, which to me is more memory intensive, no?

Someone supplied a screenie of AOE3 working with AA & HDR once, but the AOE3 devs specifically made a non-OpenEXR path for that to work, so it reverts to a non-OpenEXR path on Nvidia cards when AA is enabled...

Well that answers the other question I had last time (since people kept saying, no it's not hybrid, it's OpenEXR, etc.).

I'd still love to see this explored, because I'm still stumped as to why it would work for SSAA and not MSAA, unless there's something about the nV AA algo that just mucks things up, whereas the SSAA doesn't have that glitch. Also why not at lower res like 640x480?

To me it's likely to do with the design of the chips/rendering pipepline, but I'd have to revisit the diagrams to even begin thinking about it.

Anywhoo I'm outtie, gotta go get some meds for chect-cold, you know all that cold mountain air flowing through the lungs while bouncing down the mountains. But it's worth it! :twisted:

If I find anything more I'll definitely share, last time's effort seemed futile since no one seems to have any explanation for this issue.

 

[Heyyou27]

I posted that.

 

[Heyyou27]

I'm still stumped as to why it would work for SSAA and not MSAA, unless there's something about the nV AA algo that just mucks things up, whereas the SSAA doesn't have that glitch. Also why not at lower res like 640x480?

Super sampling runs the game at a higher resolution and then resizes it for your monitor.

 

[Acert93]

I'm still stumped as to why it would work for SSAA and not MSAA, unless there's something about the nV AA algo that just mucks things up, whereas the SSAA doesn't have that glitch. Also why not at lower res like 640x480?

Super sampling runs the game at a higher resolution and then resizes it for your monitor.

For the most part, this is why performance hits are across the board. Lets say you do a 4x sample, that means your PS have to do 4x as much work as well. This is why SSAA is such a huge hit. On the other hand it can increase image detail in certain situations and is very pretty.

 

[Heyyou27]

So you essentially restated what I said.

 

[nottheking]

I can't find one case of either SSAA or SLI-AA working along with HDR in Farcry, SPCT, or SS2, with a GF6 or GF7. If it works, which it very well could, lets see some Farcry screenshots and performance figures for dual 7900GTX. Why hasn't anyone tried it. I don't care if it's 5fps, I just would like to see a valid case of both working together. I'd think with ATI being able to do MSAA and HDR in farcry, someone with dual 7800GTX of 7900GTX would have tried to get some method of AA and HDR to work. All I see is examples and testimonials where MSAA and HDR don't work together on NV cards. Anyway, i am done searching on this.

Well, in theory, SSAA should work no matter what, given that it's a post-processing effect that's done at an even lower level than the HDR is; it simply modifies the scene setup to quadruple (or other multiple) the resolution, and then, after the whole thing is technically done, including any post-processing effects, which means also reducing the buffer to 8-bit integer, it blends it down to the actual end-result resolution. Since every card in actual gaming use today can handle 8-bit blending, this should have no problems whatsoever.

 

[ELGoku]

OMFG, Lol, I posted this 2 days ago and didn't had a chance to check it out, and it's gone up ^_^. Well yeah that was my doubt since I'm playing NFSMW and if I'm no mistaken it uses HDR on the sunlight flashes and other things, On wich I have FULL SCREEN AA enabled, and It all works fine.

But my guess that running games at higher resolutions will eventually reduce the use of AA.