Real World DirectX 10 Performance: It Ain't Pretty
by Derek Wilson on July 5, 2007 9:00 AM EST- Posted in
- GPUs
Introduction
When it was drafted, DirectX 10 promised to once again change the way developers approach real-time 3D graphics programming. Not only would graphics hardware be capable of executing short custom programs (called shaders) on vertices and fragments (pixels), but developers would be able to move much more high-level polygon work to the GPU through geometry shaders. Pulling polygon level manipulation off the CPU opens up a whole host of possibilities to the developer.
With adequate performance, many of the geometric details simulated through other techniques could be applied in simple, straightforward ways involving less overhead. Techniques like normal mapping, parallax occlusion mapping, and many others exist solely for generating the illusion of additional geometry. Ever wonder why a face can be incredibly detailed while the silhouette of the same head looks more like a stop sign than a melon? This is because modern real-time 3D relies on low polygon models augmented with pixel level "tricks" to make up for it.
There are lots of cool thing we can do with the ability to process geometry on the GPU. We could see particle systems on the GPU, fine grained model details like fur that can be affected by the physical characteristics of the world, procedural geometry for highly dynamic environments, "real" displacement mapping, and geometry amplification that can add detail to models. Some of these things may show up sooner than others in games, as we will still be limited by the performance of the hardware when it comes to implementing these features.
There are, of course, other benefits to DX10. We explored this in previous articles for those who are interested, but here's a quick run down. Object and state change overhead has been decreased, allowing for less CPU involvement when sending data to the GPU. This should improve performance and give developers more headroom in building larger, more complex scenes. We have more rigidly defined specifications, which means developers can focus less on how individual hardware will handle their game and more on the features they want to implement. With a larger focus on data types and accuracy, the results of calculations will be more consistent between hardware, and developers will have more flexibility in choosing how their data is processed.
In general, DX10 also offers a more generic computing model with lots of flexibility. This will be very important going forward, but right now developers still have de facto limitations on shader length and complexity based on the performance of the hardware that currently exists. As developers better learn how to use the flexibility they have, and as hardware designers continue to deliver higher performance year after year, we will see DirectX 10 applications slowly start to blossom into what everyone has dreamed they could be.
For now, before we get into features and performance, we would like to temper your expectations. Many of the features currently implemented in DirectX 10 could also be done using DirectX 9. Additionally, those features that are truly DX10 only either don't add much beyond what we would get otherwise, or require quite a bit of processing power to handle. Thus, we either get something that was already possible or something that requires expensive hardware.
When it was drafted, DirectX 10 promised to once again change the way developers approach real-time 3D graphics programming. Not only would graphics hardware be capable of executing short custom programs (called shaders) on vertices and fragments (pixels), but developers would be able to move much more high-level polygon work to the GPU through geometry shaders. Pulling polygon level manipulation off the CPU opens up a whole host of possibilities to the developer.
With adequate performance, many of the geometric details simulated through other techniques could be applied in simple, straightforward ways involving less overhead. Techniques like normal mapping, parallax occlusion mapping, and many others exist solely for generating the illusion of additional geometry. Ever wonder why a face can be incredibly detailed while the silhouette of the same head looks more like a stop sign than a melon? This is because modern real-time 3D relies on low polygon models augmented with pixel level "tricks" to make up for it.
There are lots of cool thing we can do with the ability to process geometry on the GPU. We could see particle systems on the GPU, fine grained model details like fur that can be affected by the physical characteristics of the world, procedural geometry for highly dynamic environments, "real" displacement mapping, and geometry amplification that can add detail to models. Some of these things may show up sooner than others in games, as we will still be limited by the performance of the hardware when it comes to implementing these features.
There are, of course, other benefits to DX10. We explored this in previous articles for those who are interested, but here's a quick run down. Object and state change overhead has been decreased, allowing for less CPU involvement when sending data to the GPU. This should improve performance and give developers more headroom in building larger, more complex scenes. We have more rigidly defined specifications, which means developers can focus less on how individual hardware will handle their game and more on the features they want to implement. With a larger focus on data types and accuracy, the results of calculations will be more consistent between hardware, and developers will have more flexibility in choosing how their data is processed.
In general, DX10 also offers a more generic computing model with lots of flexibility. This will be very important going forward, but right now developers still have de facto limitations on shader length and complexity based on the performance of the hardware that currently exists. As developers better learn how to use the flexibility they have, and as hardware designers continue to deliver higher performance year after year, we will see DirectX 10 applications slowly start to blossom into what everyone has dreamed they could be.
For now, before we get into features and performance, we would like to temper your expectations. Many of the features currently implemented in DirectX 10 could also be done using DirectX 9. Additionally, those features that are truly DX10 only either don't add much beyond what we would get otherwise, or require quite a bit of processing power to handle. Thus, we either get something that was already possible or something that requires expensive hardware.
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slickr - Monday, July 9, 2007 - link
Great review, thats what we all need to get Nvidia and ATI stop bitchin around and stealing our money with slow hardware that can't even outperform last generations hardware. If you ask me the 8800Ultra should be the middle 150$ class here and top end should be some graphic card with 320 stream processors 1GB GDDR4 clocked at 2.4GHZ and 1000MHz core clock, same from amd they need the X2900XT to be middle 150$ class and top of the line should be some graphic card with 640stream processors 1GB GDDR4 2.4GHz and 1000MHz core clock!More of this kind of reviews please so we can put to ATI and Nvidia we won't buy their hardware if its not good!!!!!!!!
ielmox - Tuesday, July 24, 2007 - link
I really enjoyed this review. I have been agonizing over selecting an affordable graphics card that will give me the kind of value I enjoyed for years from my trusty and cheap GF5900xt (which runs Prey, Oblivion, and EQ2 at decent quality and frame rates) and I am just not seeing it.I'm avoiding ATI until they bring their power use under control and generally get their act together. I'm avoiding nVidia because they're gouging the hell out of the market. And the previous generation nVidia hardware is still quite costly because nVidia know very well that they've not provided much of an upgrade with the 8xxx family, unless you are willing to pay the high prices for the 8800 series (what possessed them to use a 128bit bus on everything below the 8800?? Did they WANT their hardware to be crippled?).
As a gamer who doesn't want to be a victim of the "latest and greatest" trends, I want affordable performance and quality and I don't really see that many viable options. I believe we have this half-baked DX10 and Vista introduction to thank for it - system requirements keep rocketing upwards unreasonably but the hardware economics do not seem to be keeping pace.
AnnonymousCoward - Saturday, July 7, 2007 - link
Thanks Derek for the great review. I appreciate the "%DX10 performance of DX9" charts, too.Aberforth - Thursday, July 5, 2007 - link
This article is ridiculous. Why would Nvidia and other dx10 developers want gamers to buy G80 card for high dx10 performance? DX10 is all about optimization, the performance factor depends on how well it is implemented and not by blindly using API's. Vista's driver model is different and dx10 is different. The present state of Nvidia drivers are horrible, we can't even think of dx10 performance at this stage.the dx10 version of lost planet runs horribly eventhough it is not graphically different from dx9 version. So this isn't dx10 or GPU's fault, it's all about the code and the drivers. Also the CEO of Crytek has confirmed that Nvidia 8800 (possibly 8800GTS) and E6600 CPU can max Crysis in Dx10 mode.
Long back when dx9 came out I remember reading an article about how it sucked badly. So I'm definetly not gonna buy this one.
titan7 - Thursday, July 12, 2007 - link
No, it's not about sucky code or sucky drivers. It's about shaders. Look at how much faster cards with more shader power are in d3d9. Now in d3d10 longer, richer, prettier shaders are used that take more power to process.It's not about optimization this time as the IHVs have already figured out how to write optimized drivers, it's about raw FLOPS for shader performance.
DerekWilson - Thursday, July 5, 2007 - link
DX9 performance did (and does) "suck badly" on early DX9 hardware.DX10 is a good thing, and pushing the limits of hardware is a good thing.
Yes drivers and game code can be rocky right now, but the 162 from NVIDIA are quite stable and NV is confident in their performance. Lost planet shows that NV's drivers are at least getting close to parity with DX9.
This isn't an article about DX10 not being good, it's an article about early DX10 hardware not being capable of delivering all that DX10 has to offer.
Which is as true now as it was about early DX9 hardware.
piroroadkill - Friday, July 6, 2007 - link
Wait, performance on the Radeon 9700 Pro sucked? I seem to remember games several years later that were DirectX 9 still being playable...DerekWilson - Saturday, July 7, 2007 - link
yeah, 9700 pro sucks ... when actually running real world DX9 code.Try running BF2 at any playable setting (100% view distance, high shadows and lighting). This is really where games started using DX9 (to my knowledge, BF2 was actually the first game to require DX9 support to run).
But many other games still include the ability to run 1.x shaders rather 2.0 ... Like Oblivion can turn the detail way down to the point where there aren't any DX9 heavy features running. But if you try to enable them on a 9700 Pro it will not run well at all. I actually haven't tested Oblivion at the lowest quality so I don't know if it can be playable on a 9700 Pro, but if it is, it wouldn't even be the same game (visually).
DerekWilson - Saturday, July 7, 2007 - link
BTW, BF2 was released less than 3 years after the 9700 Pro ... (aug 02 to june 05) ...Aberforth - Thursday, July 5, 2007 - link
Fine...Just want to know why a DX10 game called Crysis was running at 2048x1536 res with 60+ FPS equipped with Geforce 8800 GTX.
crysis-online.com/?id=172