Asus EN 8800 GTX - nVidia's G80 Performance Revealed

Introducing G80 architecture and DX 10

Introduction

g80 naked

The last generation of cards saw nVidia slip well behind ATI in terms of image quality, although with their dual-PCB, dual-GPU 7950GX2 they clawed the performance crown back. This was a place that nVidia was not used to being, especially after the success of their 6 series.

DirectX 10 is a technology that we are all waiting for and both nVidia and ATI are producing cards (hopefully) in time for the release. nVidia are the first onto the market with their 8800GTX and GTS. With an architecture almost totally re-worked from the old generation, nVidia have gone all out on a unified architecture.

Asus kindly sent us their 8800GTX for a study on how the card does in real life, but first let us explore G80's features.

Outlining the technology

There's a lot of information out there on nVidia's latest gen of card so I thought I'd try to keep the explanation part simple and concise.

In the 8800GTX nVidia have implemented a parallel, unified shader design consisting of 128 individual stream processors running at 1.35 GHz. As described in my article on ATI's unified shader architecture, nVidia have made a pipeline that processes vertex, pixel, geometry, or physics operations: giving it flexibility and efficiency.

g80 architecture

So what can we see here then?

One noticible difference first of all is that nVidia have implemented ZCull before the data enters the stream processors. ZCull is a process that strips the data that you will not see out of the rendering engine. This means that the GPU does not waste time rendering stuff you will never see on screen. Previously this was implemented in post processing, meaning that vital processing power was used to render the unnecessary pixels, which were then culled afterwards.

Let's see why both nVidia and ATI think that a unified architecture was needed to increase the performance of DX10 cards:

DirectX 9 and traditional Shaders:
dx 9 pipelines

DirectX 10 Unified Shaders:
unified pipelines

So what do we have in the two pictures? In the first we see the classic non-unified pipelines with seperate vertex and pixel shader pipelines. The argument is that when you get a larger amount of either type of shader information then only one of the separate pipelines will be working to maximum effect, with "idle hardware" as nVidia put it.

Let's move onto the Unified example. Here in both geometry and pixel workloads the unified architecture excels (in theory) as the unified shader pipelines use their flexibility to render any of the information sent their way. Couple this with dynamic load balancing and you have a mightily efficient architecture that can handle anything thrown at it.

This means that you have a GPU with 128 shader processors each capable of processing pixel, vertex, geometry and physics data.

nVidia are also hoping that the flexible and efficient (and of course hugely parallel) processor in their G80 will mean that other data can also be processed.

DirectX 10

I don't want to go into too much detail with DirectX 10, as this has been covered in one of our previous articles - see here, but I'll just go over why DX10 will also add to the performance increase.

cpu overhead

dx10 pipeline

DirectX 10 reduces the CPU overhead by reducing the amount that the CPU gets involved in the rendering process. By cutting out the CPU in the most basic API processes, DirectX 10 means that the time that each object get's rendered is hugely reduced. Let's look at it like this (ATI slide)

ati dx 10 slide

DirectX 10 solves this by working towards general processing units. The new Geometry Shader can manipulate Vertexes and many other types of objects. This means that it has more ways to process, access and move data. This extra level of manipulation adds a lot of headroom for developers to introduce new features into games and to utilise the GPU for more than just rendering of a scene.

So Geometry Shaders can manipulate data...how do the developers use this?

Well basically I'm hoping that developers will use this to do things like stop "pop-up" (of trees/objects etc in the distance). I can see that there would be a huge advantage in using these units to change things like water over distance and adding far superior rendering to characters that are in the periphery of games: such as excellent crowd animation in racing/sports games. This is all my own speculation, but it would certainly be nice to see.

Memory interface mid-process

Also added into nVidia's "Stream" processors is the ability to move data to memory and back again in one pass. This means that you should no longer require data to have two or more passes before it can be outputted. Once again this adds to the picture of added efficiency that nVidia are building up.

Instancing

Shader Model 3 brought far superior instancing than we had seen before. Instancing means that you can render one object and replicate it a whole load of times, creating a fuller effect. This is very useful in trees and grass where you need to replicate basically the same thing many times over.

instancing

128-Bit High Dynamic Range

nVidia have implemented 32-bit floating-point precision for a total of 128bits dynamic-range rendering. They claim this is a quality of accuracy that outperforms film renders

This is enough detail for this article at the moment, but I may do a fuller article on this in the future.
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Most Recent Comments

24-12-2007, 16:39:23

FarFarAway
Been waiting for the OC3D to take a look at the 8800 GTS 512mb G92?

http://www.overclock3d.net/gfx/artic...205838708s.jpg

Well I've been working hard

Take a look!

24-12-2007, 17:24:49

Rastalovich
Great insight into the higher end of the gpu spectrum.

I have to be fair, even tho u`ve got a 1 to 4 positioning, I don`t think there`s that much in it for any of them. I know the Ati slides in the rankings, but it does show itself to be a fine card.

An interesting comparison would have been performance versus costing, seeing as they`re as close as they appear to be.

I`m a bit at odds with the oc results too. I simply can`t achieve the memory overclock on my GT without it having fits. But I can clock the gpu to around 720 (from 670).

What would impress me is some1 buying the cheapest GT, putting it under water, and claiming back those clock hertz with their superior cooling. Sounds nice.

Suprizes me a bit tho that the GTS isn`t launched as a bigger performer. Although pricewize, it does seem to start from stock where the GT limit starts. Leaving u further to climb

Nice review m8, think every1s doing the "going to bed early to get up early" trick

24-12-2007, 17:25:40

Hyper
Nice to see this review is finally up

Shame I cant view it as 128k is painfully slow :sleep:

24-12-2007, 18:07:43

Hatman
Thing is though there is a BIOS voltmod for the 8800GT that GREATLY increases its overclockability. If there isn't one for the 8800GTS I see them both reaching high limits but so far the 8800GT seems to OC better. With good cooling and the volt mod this thing easily passes 800mhz core, I've seen some at 850+.

What you also go to look at as well is shaders, they seem to be the key thing atm if the shaders OC much better on the 8800GT, which I guess they kinda should since they could simply lock the worst performing ones to get it top out better, it could impact performance in certain titles a lot.

Nice review though I was surprised the 8800GT didn't clock more, there wasn't a heat issue was there?

It should also be said about the supposed problems of the memory modules on the 8800GT, seems that long term use of the memory at 2ghz+ and it brakes. Thats why some companies like Zotac use better memory modules for their cards.

24-12-2007, 18:29:40

Brooksie
Great review Kempez, can't wait to open my GTS tomorrow

24-12-2007, 18:34:22

FarFarAway
The GT was a little hot yes, but I will never change the cooling or take off the heatsink prior to running any tests. I test every card as it would be when it appears on your doorstep

Volt-modding is not part of the overclocking testing as the percentage of users who do that is small and it voids any warranty you have.

An overclock is dependent on what RAM is used, what cooling is like and also what luck you get with the silicon...the overclocking gods didn't smile on me this time

@Rast: I agree, the ATI card is a great card as I said in the ATI review, but this review was for these two cards. Having said that: would I buy the HD3850 personally? No, I'd go for an 8800 GTS 512mb G92 or an 8800 GT 512 G92 It's simply not fast enough with every game, I'm afraid.

24-12-2007, 20:56:32

Deshman
I've just got my hands on one of those new GTS's and was achieving much higher frames in Crysis than you were quoting there, could you tell me the AA levels it was running on and was it DX9 or DX10?

25-12-2007, 04:39:46

FarFarAway
DX10 settings high with no AA

25-12-2007, 04:51:09

Toxcity
Well done Kemp!

I loved that read, very interesting.

25-12-2007, 15:45:19

jabski
great review. very informative

25-12-2007, 17:21:27

Drakelet
Great review!

I'm looking to get a new graphics card within the next 3 months or so, and I'll spend up to about £200 (although £180 is more preferable). What would you recommend? I was thinking an 8800GT (which this review makes me think would be a good choice!) or, well, something else, like the ATi 3850.

Thoughts?

Quote:
Originally Posted by name='Hyper'
Shame I cant view it as 128k is painfully slow :sleep:
What a crap excuse! :P I have 37.2kb/s. Where there's a will there's a way damnit!!

25-12-2007, 17:32:13

Deshman
Quote:
Originally Posted by name='Drakelet'
Great review!

I'm looking to get a new graphics card within the next 3 months or so, and I'll spend up to about £200 (although £180 is more preferable). What would you recommend? I was thinking an 8800GT (which this review makes me think would be a good choice!) or, well, something else, like the ATi 3850.

Thoughts?
Go for a low end GTS, it'll last longer than a GT.

25-12-2007, 17:42:29

Drakelet
Wow, that was quick!

You mean the new GTSs or old GTSs? And by last longer, do you mean futureproofness or physically last longer?

I just looked on Dabs and Ebuyer for GTSs (where I would nearly certainly buy from), and they were all >£200 (apart from a Dabs Extra Value one).

I've just been doing some research and came across the Sapphire HD3870.

I've never been a fan of Sapphire - Always been an XFX/BFG person. Sapphire just seem cheap, and cheap scares me. I've read a lot of reviews (well, 3) though, and each time it's got 9/10. So, it seems pretty damn good, and £40 cheaper than the XFX 8800GT. Plus it has higher clock speeds, and DDR4.

I said I would go up to £200, which I will, just ATM I have nothing, so the less it is the sooner I can get it, and £40 cuts off a couple weeks at least.

HD3870 - http://www.dabs.com/productview.aspx...1137,415920000

8800GT - http://www.ebuyer.com/product/138713/show_product_specifications

Thoughts?

EDIT: I've just heard about ATi drivers being crap. Are they? There are always custom drivers I suppose, like those at TweakForce.com.

Sorry about the thread-hijack BTW, I'll probably take it to a new thread in a minute. Post here for now though.

25-12-2007, 18:16:42

Deshman
Obviously the new GTS

By last longer I mean it has the extra stream processors which will hold back a future upgrade just a little bit more You certainly notice the difference in Crysis imo.

I'm not sure if it's just that card but we've tested 2 of XFX's Xtreme 8800GTs and they both produced jagged coloured artifacts and had to be sent back faulty. However in comparison we've tested two of the new Xtreme GTS from XFX which will set you back £30 more and they performed flawlessly.

Personal opinion is to go for the GTS but if cash is really that tight then go for the GT. Unfortunately these are both the best value cards at the moment if you want a good price/performance ratio.

25-12-2007, 19:14:00

FarFarAway
Glad you lads liked the review and that it was some use to you.

If you have a screen under 1680 x 1050 then a GT is the way to go. If you're over that then get a GTS imo

26-12-2007, 05:40:45

Drakelet
So forget about the ATi completely?

My screen is under 1680x1050.

Deshman - Where d'you get the cards? The 8800GT Extreme is £180 delivered, which isn't too bad, but I can't find a 8800GTS Extreme for ~£210.

26-12-2007, 05:58:04

FragTek
Great review Kemp! Noticed one small correction, 5th page second para: "When the resolution was upped, the more generously stream processor endowed 8800 GTS comes out 2nd <--- Looks like it comes in 3rd to me? with it's bigger brother, the 8800 GTX taking the win."

26-12-2007, 08:32:41

Bungral
4th paragraph after the 1st pic on the 1st page:

All this leads me to think that the G92 8800 GT should be a rather fast GPU and possibly a match for the 8800 GTX. Be aware though, it's not going to touch it's higher end predecessor the 8800 Ultra, as Nvidia's flagship model still has over 60% more memory bandwidth and 40% more pixel fillrate.

Should it say:

All this leads me to think that the G92 8800 GTS should be a rather fast GPU and possibly a match for the 8800 GTX. Be aware though, it's not going to touch it's higher end predecessor the 8800 Ultra, as Nvidia's flagship model still has over 60% more memory bandwidth and 40% more pixel fillrate.

Don't mean to be pedantic but as its actually the name of the card I thought I'd mention it .

1 more too:

Of course, we have to mention that the G92 is fabricated by TSMC on a 45nm process.

65mn??

Thats just above the table on comparing all the cards.

Now... Back to reading the review

26-12-2007, 09:02:42

Bungral
Ok finished the reading very nicely done Kempez... Must have taken a fair while??

I think what surprised me the most was how close all 3 were.. I knew the GTX still beat the GT but I thought the gap was bigger... Its such a small gap to try and fit the new GTS into. They obviously didn't want it to come out and trash the more expensive GTX but didn't want it out and get whipped by the cheaper GT...

Oh yeah 1 more correction too

Conclusion

It's actually wrong to separate these two cards based simply on pure performance along.

Enjoyed reading that.. So again nice one!

26-12-2007, 09:16:24

FarFarAway
Thanks Bungral

All corrected

And yep, it did indeed take a long time

26-12-2007, 14:25:46

!TIMMY!
If u do buy a Asus 8800GT then you might get it with a 2 slot cooler:

http://upload.overclock3d.net/dwn/26...0/cimg3966.jpg

I thought i was getting one with the stock cooler but hey, although there doesnt seem to be any ram sinks which worries me with ocing (I think most ram on 8800GT's are rated to run @ 1000):

http://upload.overclock3d.net/dwn/26...1/cimg3967.jpg

Just a heads up for people if they go with Asus.

Nice review Kemp, might have to oc this bad boy and get it closer to a 8800GTS 512.

26-12-2007, 14:54:52

Hatman
I just put the EK block on mine looks sooo kl on water although I dont have any sticky pads?? Used AC5 for the ram chips but nothing 4 the mosfets on the card mmm...

26-12-2007, 20:56:51

Deshman
Quote:
Originally Posted by name='Drakelet'
So forget about the ATi completely?

My screen is under 1680x1050.

Deshman - Where d'you get the cards? The 8800GT Extreme is £180 delivered, which isn't too bad, but I can't find a 8800GTS Extreme for ~£210.
Got them from specialtech but they're out of stock now.

08-01-2008, 08:22:49

PV5150
A great and informative review as always Kemp, and one which will make a potential purchasing decision easier. Well done!

08-01-2008, 14:28:38

FarFarAway
Thanks mate, that's the idea and glad you liked the review

17-01-2008, 08:32:54

Paradisos
Can please someone be more specific about the noise on the asus card ?

I mean is it really annoiing when playing games like crysis with full load ?

I guess when not playing games it should be no problem right ?

17-01-2008, 09:12:20

Bungral
Quote:
Originally Posted by name='Paradisos'
Can please someone be more specific about the noise on the asus card ?

I mean is it really annoiing when playing games like crysis with full load ?

I guess when not playing games it should be no problem right ?
Its only loud when its at full speed which only happens when the card gets a bit warm.. You can always change at what temps the card switches speed of the fan.. Thats what I do.

My card sits at 20% fan speed up to 55 degs so you can't hear it at all when not gaming then at 57 degs it jumps to 40% still can't hear it. 60 degs and it jumps to 60% and 65 degs it would jump to 80% which you can hear...

100% is a touch annoying but you can't hear it if using a headset obviously.

17-01-2008, 09:24:54

Paradisos
Thanks Bungral !

Although i don't intend to use headset, i guess playing a game with a 5.1 surround sound wont let you notice the fan noice of the gpu, so i guess i will be ok.
Reply
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