Shader Model 3 & 4

Would there be any difference in performance of the Shader Model 4- en Shader Model 3 cards?

 

Shader Model 3 cards will not be able to render using shader model four at all.. the game will have to either display in SM3 or the game will be entirely unplayable. An example of this would be attempting to play a game like Bioshock (SM3 only) on a card that only supports SM2 and lower... the game does not play.

 

But would a Shader Model 4 card be faster when playing a game with Shader Model 3 then a Shader Model 3 card?

 

not exacly... for example... ati x800 is sm2.0b card and its a lot faster than many sm3 cards in sm2 applications and games.... some cards have more raw power...
7900 is still faster than 8600 as far as i know, althrough 8600 is sm4 card

 

That would have nothing to do with speed. Yes, it probably would be, since an SM4 card would have to be newer, but newer isn't always faster. Just to re-iterate, it ONLY affects a render mode, NOT a render speed. A better question would be "Will this [insert card] outperform this [insert another card]?" Because SM is kinda like direct x. A DX10 capable card will not play a DX9 game better, it will just be able to play games in DX10 and earlier. So... a 7950GT or 7900GTX, both DX9 capable cards, will outperform an 8400GS by quite a margin, even though the 8400GS is DX10 capable. Hopefully I am being clear.

 

Which cards are you looking at? Because sometimes, despite a card having support for a newer shader model, the card itself is too slow to actually run any games that implement that shader model.

A card supporting SM4 simply means that it can run the more fancy eye candy. Whether it will run the eye candy well depends on the clock speed and memory of the card.

 

Sure it does, all you need is one of the shadershock patches.

 

Same for Oblivion on DX8 cards and FO3 for SM2.0 cards.. some shader butching

Btw SM4.0 is only on DX10, so unless you have Vista the card will only uses SM3.0 on Windows XP

 

Yeah, that's actually how I played Bioshock the first time, but natively the games does not play.