No SM 3.0 Support = ???

T

Talonz

2[H]4U
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Hey guys, this is a question that's been bugging me lately:

What happens when a game requires SM 3.0 but a card only supports SM 2.0?

Does it refuse to run or do the drivers translate the instructions to SM 2.0?

Thanks
 
The game will run, just without the Shader Model 3.0 effects.
Most games have a Shader Model 2.0 fallback, and if that doesn't work then it will run without any shader effects period... ala DX7 or whatever.

The game will run though.
 
Talonz said:
Hey guys, this is a question that's been bugging me lately:

What happens when a game requires SM 3.0 but a card only supports SM 2.0?

Does it refuse to run or do the drivers translate the instructions to SM 2.0?

Thanks
Click to expand...
There are currently no games that require Shader Model 3.0, and only 1 game that requires Shader Model 2.0 to run, if it requires Shader Model 3.0, then the game simply won't run at all on Shader Model 2.0 hardware.

This however will take sometime to come, expect no game to require Shader Model 3.0 till 3.5 years after the intorudction of Shader Model 3.0 hardware so I bet Late 2007 at the aboslute earliest.
 
Right now 1.1, 1.3 and 1.4 shaders are all being phased out and the 2.0 shaders will become a requirement so ya 3.5-4 years before you see a game that requires 3.0.
 
SM3.0 doesn't really do much except give a more efficient code path to do certain effects. The effects that SM3.0 help with are still doable in SM2.0, which all dx9 level cards support. They're just processed slower. If your card is only SM2.0 capable and the game uses SM3.0 effects, then either you will not see the effects at all, or in most cases, the effects will just be coded to work with SM2.0, although they'll be a bit harder on the framerate.

No games will simply not work without sm3.0 hardware. At least not for a long, long time. That would be a boneheaded move on the part of the company making the game.
 
Is true, there's no SM 3.0 effect that cannot be done under 2.0, but will require multi passing if the shaders are long. But there''s exceptions to the rule like SM 2.0a and 2.0b, both can run longer shaders, particularly the 2.0b that is pretty much a SM 3.0 without Dynamic Flow Control. The SM 3.0 like the SM 2.0b has only 512 Pixel Shader Instruction Slots for each component like Scalar, Vector and Texture, but with the help of Dynamic Flow Control, the SM 3.0 can output up to 65k instructions, while the SM 2.0b will only output their total, (1,536 per pass), more can be done with the F - Buffer but it cannot be implemented in DX but in Open GL. The Dynamic Flow Control must be used carefully, or a huge performance hit will happen.
 
I doubt SM 3.0 will become a "requirement", even though I have an SM 3.0 capable hardware. You'll see SM 4.0 as a "requirement" sooner in my opinion as DirectX 10 requires that model.

Of course Vista will have 9.0L fall back for those games that support that and are not DirectX 10 "only". 9.0L "may" be SM 3.0 required, but I think it'll pretty much mirror the current state of DirectX 9.
 
Cant direct x9 get more effecient too in the future. At the mo there is directx 9c ,so what is the c for and is this the proof that it is more effiecient than the last meaning DX9 b?

Also if this is true then arent we going to see this intime for vista because 99% of us will be relying on it ? :confused:
 
M$ wants people to buy windows vista, the only reason a gamer would want to upgrade to vista from xp is DX10. Now why would they improve on DX9? To continue support for windows xp? I think not.
 
nooh said:
Cant direct x9 get more effecient too in the future. At the mo there is directx 9c ,so what is the c for and is this the proof that it is more effiecient than the last meaning DX9 b?

Also if this is true then arent we going to see this intime for vista because 99% of us will be relying on it ? :confused:
Click to expand...

1. yes, MS was proud to point out back in the day that dx9 was infinitely scalable/expandable and was the last real version of directx they'd have to release. However, it looks like the marketing guys took things over and now they're releasing dx10 for vista-only and they're discontinuing the dx9 series, in order to force people to migrate to vista. Also, even though dx9 was infinitely scalable that doesn't mean it was perfect. dx10 improves things considerably by reducing API overhead and making directx itself work more effeciently and take less processor time.

2. the letters just indicate the sub-version of direct x. The whole point of dx9 was that it could just be "extended" to incorporate new shader features. For example, SM3.0 was never even in the original release of dx9...it was added with the "c" revision. I'm sure there are many more differences, but the main differences between them are as follows:

dx9: original release, SM2.0
dx9b: added ps2.0a and ps2.0b (as described by a previous poster)
dx9c: added SM3.0
 
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