HDR+AA...Possible with the R520?

[shadow]

I've been reading all the reviews of the 7800 GTX,and while it's performance is very good,it seems to be unable to handle HDR+AA,just like the 6800 couldn't either,not even in SLI mode.


I've been hearing that it's has mostly to do with the massive memory bandwith requirements,and the need for compression formats for all data types,and so far,it seems that the only graphics chip that can pull it off to some basic degree(HDR using FP 16 + MSAA) is the Xenos in the X-box 2. since the link between the GPU and Edram is so fast at 256 Gb/sec of memory bandwith..


So the question is,since ATi did design the xenos,could it have found a way to implement it in the R520 as well,without having to resort to eDRAM?...I see that as a major advantage if it has that capability,even with the delays it's suffered and it wouldn't even matter if Nvidia released a faster clocked 7800 ultra right after the R520 release...

 

[Geeforcer]

First of all, the bandwidth between eDRAM and GPU in Xenos is 32GB/s. Second, Dave seemed to be dropping hits as of late that R520 will indeed allow for HDR and AA.

 

[shadow]

First of all, the bandwidth between eDRAM and GPU in Xenos is 32GB/s. Second, Dave seemed to be dropping hits as of late that R520 will indeed allow for HDR and AA.

Would be an awsome advantage over the 7800 if ATI can pull it off with the R520,even if it would be any faster than the 7800 in current games...

 

[shadow]

First of all, the bandwidth between eDRAM and GPU in Xenos is 32GB/s. Second, Dave seemed to be dropping hits as of late that R520 will indeed allow for HDR and AA.

Actually,it does have 256 GB/sec of bandwith between the ROP's and eDRAM,as both are integrated in the daughter die,and that's where the bandwith needs are met in order to allow HDR+AA...


[url]http://www.beyond3d.com/articles/xenos/index.php?p=03 [/url]

 

[The_Wolf_Who_Cried_Boy]

So the question is....ATi ......implement it in the R520

Considering

A] ATi have said they would not do shader model 3 till 90nm so as they could do it properly,

and

B] Those forum members who would actually know suggest the pipe count has not increased over X850,

would suggest the transistor budget would have room for features like antialaised HDR.

/Pure armchair speculation of coarse.

 

[shadow]

So the question is....ATi ......implement it in the R520

Considering

A] ATi have said they would not do shader model 3 till 90nm so as they could do it properly,

and

B] Those forum members who would actually know suggest the pipe count has not increased over X850,

would suggest the transistor budget would have room for features like antialaised HDR.

/Pure armchair speculation of coarse.

On that note,then it could be possible that if we assume the pipeline count isn't being increased on the R520,and that the 7800 is a 300 million transistor part at 0.11 micron,while the R520 a 0.90 part,meaning the fab process allows an even higher transistor count than the 7800,while keeping the overall Die size the same or less than the 7800,that it can potentially allow enough transistor budget to integrate both SM3.0 and eDRAM on the same Die?.....

 

[The_Wolf_Who_Cried_Boy]

Not with the R520.


http://www.bit-tech.net/preview/bits/richard_huddy_ati/1.html

By now, you’d have to have been hidden under a rock to have avoided learning the details of the ATI graphics that power the 360, dubbed Xenos. 10MB of Embedded DRAM provide enough of a buffer to enable all 360 games to have Anti-Aliasing switched on, effectively for no performance hit. The question on everyone’s lips is: is this something that’s going to turn up on the PC any time soon?

“I’d be very surprised if these hardware features were implemented on the PC any time soon,â€￾ we’re told. “Microsoft has a very specific revision of DirectX (or Windows Graphics Foundation) for Xbox 360, just as they did with Xbox 1. DirectX for the PC includes no hardware specific instructions, because DirectX has to be 10 times more generic to work on a PC platform and the myriad of hardware configurations. I don’t think it will happen. Plus the architecture of the Xbox 360 is closed box – that means we can do special things there which have no comparison in the PC space.

"We practically have AA for free on the PC anyway right now. If the difference between 1280x1024 with no AA and 1280x1024 with 2x AA is 90 FPS and 70FPS, who wouldn’t turn the AA on? The performance hit isn’t going to be noticeable to most gamers – and with an X800 or X850 those kind of frame rates are common place.â€￾

 

[shadow]

Not with the R520.


http://www.bit-tech.net/preview/bits/richard_huddy_ati/1.html

By now, you’d have to have been hidden under a rock to have avoided learning the details of the ATI graphics that power the 360, dubbed Xenos. 10MB of Embedded DRAM provide enough of a buffer to enable all 360 games to have Anti-Aliasing switched on, effectively for no performance hit. The question on everyone’s lips is: is this something that’s going to turn up on the PC any time soon?

“I’d be very surprised if these hardware features were implemented on the PC any time soon,†we’re told. “Microsoft has a very specific revision of DirectX (or Windows Graphics Foundation) for Xbox 360, just as they did with Xbox 1. DirectX for the PC includes no hardware specific instructions, because DirectX has to be 10 times more generic to work on a PC platform and the myriad of hardware configurations. I don’t think it will happen. Plus the architecture of the Xbox 360 is closed box – that means we can do special things there which have no comparison in the PC space.

"We practically have AA for free on the PC anyway right now. If the difference between 1280x1024 with no AA and 1280x1024 with 2x AA is 90 FPS and 70FPS, who wouldn’t turn the AA on? The performance hit isn’t going to be noticeable to most gamers – and with an X800 or X850 those kind of frame rates are common place.â€

Scratch that idea then ...

Still,if the R520 is to remain a 16 pipe card at potentially 300+ million transistors at 0.90 micron,and even if we figure in the transistor budget needed for H264 hardware playback support and SM 3.0,there still seems a lot of transistor budget left over for something extra....


The X800 cards use up about 160 million transistors,so it seems to me that having another 160 on top of that should give a lot of options that go beyond SM 3.0 and H264 playback support...

 

[Ailuros]

First of all, the bandwidth between eDRAM and GPU in Xenos is 32GB/s. Second, Dave seemed to be dropping hits as of late that R520 will indeed allow for HDR and AA.

Actually,it does have 256 GB/sec of bandwith between the ROP's and eDRAM,as both are integrated in the daughter die,and that's where the bandwith needs are met in order to allow HDR+AA...


[url]http://www.beyond3d.com/articles/xenos/index.php?p=03 [/url]

Depends what you mean with HDR; bandwidth this and bandwidth that, I doubt you can even fit both float HDR and 4xMSAA into just 10MB eDRAM, but that's just probably me.

 

[aaaaa00]

Depends what you mean with HDR; bandwidth this and bandwidth that, I doubt you can even fit both float HDR and 4xMSAA into just 10MB eDRAM, but that's just probably me.

Absolutely you can, but you have to render more tiles. Tradeoffs, tradeoffs.

 

[jimmyjames123]

It seems somewhat clear to me that ATI will have AA + HDR working on the R520. Notice how many reviewers were claiming it was a shame that NV 7800GTX does not have AA + HDR. This can only mean one thing in my opinion...that ATI is planning on doing it.

 

[Acert93]

Depends what you mean with HDR; bandwidth this and bandwidth that, I doubt you can even fit both float HDR and 4xMSAA into just 10MB eDRAM, but that's just probably me.

Absolutely you can, but you have to render more tiles. Tradeoffs, tradeoffs.

Correct.

Technically you cannot fit 4x FSAA @ 720p in the 10MB eDRAM. You cannot even fit 2x FSAA. 2x FSAA is 2 tiles and 4x FSAA is 3 tiles.

ATI has said 2x is free and 4x is a 1-5% hit in performance. So we may see some developers who get ambitious and go all out, or in the least, 2x AA + FP16. But in the end the FP10 sounds respectable enough for most uses.

http://www.beyond3d.com/articles/xenos/index.php?p=05#tiled

 

[Acert93]

It seems somewhat clear to me that ATI will have AA + HDR working on the R520. Notice how many reviewers were claiming it was a shame that NV 7800GTX does not have AA + HDR. This can only mean one thing in my opinion...that ATI is planning on doing it.

I would not read that much into it.

As an NV40 owner I can say it is a shame that HDR is too slow to use, and a double shame it does not work with AA because AA really improves IQ.

Now that HDR is working nicely on G70, it is tradeoffs. HDR or AA. That is a crappy tradeoff in my book! I want both! But seeing as the couple games that use HDR are pretty spotty on its implimentation, I would have to say AA wins out.

Which is sad because we should not have to choose better lighting or better IQ. I am dissappointed without even knowing whether R520 will have it or not. It has been a year since NV40's launch. HDR speed and AA + HDR were some of the biggest complaints last year (outside of SM 3.0 effeciency questions). I would have rather NV make HDR work with AA at good framerates rather than double MAD performance. But that is just me.

So I would not read too much into it... yet

 

[jvd]

So I would not read too much into it... yet

ati could offer hdr fp 10 and hdr fp 16 both with fsaa .

Fp10 should be usable with moderate fsaa lvls depending on the game. Mabye 4x fsaa .

 

[RejZoR]

There isn't any real HDR enabled game yet anyway (except Far Cry). Why bother? Other games use Bloom effect which does nearly the same effect much cheaper.

 

[jvd]

There isn't any real HDR enabled game yet anyway (except Far Cry). Why bother? Other games use Bloom effect which does nearly the same effect much cheaper.

because in a few months (5) the next gen systems are coming out and hdr will be widely used . Esp on the x360 that has fp 10 hdr which should provide a much smaller hit than fp 16 . The x360 can do fsaa on these images .

So in i would say 6 months or so we will start to get alot of games with hdr coming out and then when the ps3 comes out that output will ramp up even more with two consoles worth of ports coming to the pc and vice versa

 

[Farid]

Personally, the question I'd like to ask is :"Does R520 have a 16fp or 10fp precision for the framebuffer"?

 

[DemoCoder]

all those games will have to be backwards compatible with existing NV4x/R3xx HDR techniques.

 

[Dave Baumann]

It seems somewhat clear to me that ATI will have AA + HDR working on the R520. Notice how many reviewers were claiming it was a shame that NV 7800GTX does not have AA + HDR. This can only mean one thing in my opinion...that ATI is planning on doing it.

Irrespective of whether its works on R5x0 or not I'd say its a shame because a.) this is one of the most frequent queries that I noticed prior to the release of G70, b.) developers have to take into account this loss of orthogonality in the ROP's between HDR and MSAA, c.) Its a hard trade-off of one IQ feature to the next - inevitably end users will be trading something off for performance, but if it were available they may find they can strike a balance they like between res, AA depth and HDR.

Inevitably it will go away for everbody eventually as the decision is purely down to transistor budgets.

 

[Dave Baumann]

Personally, the question I'd like to ask is :"Does R520 have a 16fp or 10fp precision for the framebuffer"?

Would it need to be an either/or situation?