ALL current ATI cards cannot run future Valve titles?

[EglsFly]

After reading this article:
http://www.tomshardware.com/business/20030911/index.html

There is one thing in this article that really caught my attention.
The note about 32-bit shaders being REQUIRED in future games.

Valve was able to heavily increase the performance of the NVIDIA cards with the optimized path but Valve warns that such optimizations won't be possible in future titles, because future shaders will be more complex and will thus need full 32-bit precision.

Basically the nVidia performance stinks for this game, we know that now. If the new 5x.xx drivers fix it, then so be it, and that will be great for those cards and then they can run future Valve games.

However, the current crop of ATI cards only have 24-bit shaders!
So would that make ALL current ATI cards without any way to run future Valve titles?

Perhaps I do not understand the technology fully, can someone elaborate on this?

 

[kylebisme]

i responded in the other thread but i'll explain it better here. bascly, ya some shaders might look bad when rendered with 24-bit floating point, in which case it would be necessary to substitute it with another shader to get an acceptable effect; kinda like valve is doing with hl2 and nvidia cards but lowering the precision for performance reasons, not because the hardware can't do it.

the thing is dx9 calls for fp24, so that was the plan for everyone to program for. nvidia decided to shoot for high quality with fp32 and also have the ability drop to fp16 and fx12, so developers would have the option to lower precision to gain performance. unfortunately, the fx series are slow in any floating point precision and only the nv35 gets any real boost from dropping to fp16; but even then the nv35 doesn't keep up with newer radeons very well and while obviously having the possibility of looking worse due to lower precision.

so anyway to answer your question, some day the current ati cards will not run valve games, or others for that matter, with all the eycandy on; they will still run them but obviously not with fp32 shaders. but then that is what is supposed to happen when videocards get old, you can't run games with all the fancy new features. unfortunately that kinda makes nvidias brand new 500$ videocards look rather old already.

 

[McArra]

In my town it is called evolution.

If I were you I wouldn't trust a lot in Tom's.

 

[gramboh]

So fp24 is full precision under DX9 correct? And this should not change until DirectX 10 is released? By that time (when DX10 games are mainstream) current generation cards will be extinct.

I think the Valve quote is saying that as time goes on, and new Source engine games/content/mods are released, less and less work will be focused on the special Nvidia code path because of the cost whereas the ATI seems to be able to run it at spec.

 

[PricklyPete]

The DX9 spec asks for 24bit floating point...not 32bit. nVidia going with 32 bit is noble and all, but it is not necessary to follow DX9 spec. also, the difference between 16bit and 24bit is significantly larger than the difference between 24bit and 32 bit visually (bit wise...they are obviously the same).

As long as developers are using DX9 to write their code...ATI will have no problem running any upcoming games. When DX10 comes out...none of the current cards will support the new features....and I'm sure ATI and nVidia will have awesome cards at the time to take advantage of those features.

 

[DaveSimmons]

> the difference between 16bit and 24bit is significantly larger than the difference between 24bit and 32 bit visually

Exactly. for example with 16-bit color there are only 65,536 distinct colors and showing a photograph you either see color banding or blocky dithering. 24-bit moves you to 16.7 million colors and there is no banding or dithering.

With floating-point numbers there is a similar 256-fold increase in precision. Valve's point wasn't so much that 32 bits are needed as that 32 bits are needed by nvidia, instead of low-quality but fast 16-bit. Right now some low-quality 16-bit shading is acceptable for HL2 to get the framerate up, but Valve is saying it's a short-term hack.

 

[tenoc]

There was about a five-year gap between HL and HL2, IIRC.

So in another five years I fully expect to have to a replacement for my 9700P to run HL3.

 

[Lonyo]

Valve was able to heavily increase the performance of the NVIDIA cards with the optimized path but Valve warns that such optimizations won't be possible in future titles, because future shaders will be more complex and will thus need full 32-bit precision.

DX9 calls for 24-bit precision.
As Nvidia can do 16-bit or 32-bit, when a game calls for 24-bit precision (this is what they will call for) it will have to go through nVidia's 32-bit precision, and ATi's 24-bit precision.

Gabe is only talking in reference to nVidia, as the call will be for 24-bit, which will be done in 32-bit by nVidia, since that's the only option it will have, and they won't be able to use 16-bit, hence optimisations of redcing the precision to 16-bit on nVidia card's won't work.

 

[NelsonMuntz]

So why in the world did NVIDIA go with 32 bit?
They must have been figuring that since they
could do 16 bit with good performance then the
32 bit registers could each take 2 16 bit chunks
easily thus making the 16 bit to 32 bit conversion
more efficient.
Why not go 24 bit with the ability to drop back to
12 bit? They must have figured everybody would
notice the drop to 12 bit but not the drop to 16 bit
as much - or something like that.