Speculation about NV40 DX9 capabilities

[Carfax]

I read somewhere that having 8x2 pipeline setup will cripple the NV40 in DX9 games.

The reason being, that it can't fit 2 DX9 instructions through the pipeline so it will essentially be acting like a 8x1 card for DX9 rather than a 8x2 card..

How true is this? I'm no expert or anything nor do I claim to be, but I was curious as to the truth of that statement.

[Nutty]

The 2 refers to the number of textures it can access simultaneously without any performance penalty.

For example the GF4 is a 4x2, meaning it has 4 pipes, and can access upto 2 textures at full speed.

The R300s 8x1 design meant to access more than 1 texture causes additional performance penalties. Ideally you want as many physical texture units per pipe as possible, as the future of games will be using alot of textures per pass.

[Carfax]

Yes, but can a DX9 texture be accessed two at a time? Thats what I'm getting at. I heard that the NV40 can access two textures with DX8 textures, but not DX9.

[Carfax]

Nevermind, I found the answer! LOL

[Nutty]

NV30 and upwards allow you to access upto 16 textures in a fragment program. (pixel shader). And you can access a single texture more than once.

[Paul]

This thread needs to hurry up and die. Being an 8x2 hurts it? You'd rather it was an 8x1? 8x0?

[rwolf]

Originally posted by Paul
This thread needs to hurry up and die. Being an 8x2 hurts it? You'd rather it was an 8x1? 8x0?

Why is that? As long as you have the bandwidth to read all those textures and enough pipelining to hide the latency what is the problem?

[Uttar]

It's not like the NV40 was 8x2 AFAIK, so I hardly see how this discussion matters anymore :p


Uttar