Pixel Pipelines

[gokusgrill]

i can never seem to find a site that can give me a straight detailed answer.....what exactly do pixel pipelines do and how does it work?

[lilkev715]

http://www.anandtech.com/video/showdoc.aspx?i=2552&p=3

 

That might be abke to help you out a little, if not there is always google.

[Enyce2k9]

i just think of it as "more bandwidth, more Xper sec"

[Cookieman123]

http://www.anandtech.com/video/showdoc.aspx?i=2552&p=3

 

That might be abke to help you out a little, if not there is always google.

591012[/snapback]

*head explodes*

[Kamikaze_Badger]

As far as I know, pipes handle various specific functions (at least some do). For example, p1a1 may handle calculations only with double float precision, p2a1 may handle geometric calculations, and so on. I believe that you can get a list of what each pipe does from either nVidia or ATI, usually in the form of a... what's the word... programming manual.

[gokusgrill]

i wanted to know because there was all that talk about nvidia being better because their

7800 gtx had 24 pixel pipelines while ati only had up to 16. alot of people were focused on the importance so i needed to know why.

[Kamikaze_Badger]

Consider them to be workers, then. Now, consider the cards to be contractors. The X1800XT has 16 workers, who can't do jobs as effeciently as 24 workers by the 7800GTX can.

[Enyce2k9]

heh good example

[Kamikaze_Badger]

However, I'm not all that sure. Video cards are amazingly complex. What makes it worse is that unless you have really really REALLY steady hands and an electron microscope, you won't be seeing how they truly work deep down for quite awhile. The closest you'll get is a programming optimization PDF (Thank you so much nVidia).

 

And, after reading the stuff at Anandtech, it seems that at least on the X1800XT, each pixel shader quad has a certain job. One handles fog and smoke, the other textures maybe, another Z axis, etc. Distribution like this helps keep bottlenecks down. Each pipeline can do 6 instructions per clock cycle. So, at 500 Mhz, that's... 3,500 4x4 pixel shader blocks, however it also depends on the programmer and optimizations for that specific core.

 

The whole ring bus memory system I'm still trying to grasp, and I sort of just skimmed through that part. Overall, you've gotta respect the guys who build this stuff. It's complex, and while some algorithms are built into the hardware, it has to handle a . load of crap. Not to mention complications regarding the chance of a RAMDAC bottleneck.

Edited December 7, 2005 by Kamikaze_Badger

[Archerzz]

More = Better

[swifty11212]

just because the x1800xt has 16 pipes doesnt mean it cant do a good job, hell the xl is just as good as the 7800gt card. but the example of more is better is good, but too much isnt a good thing imo.

[Kamikaze_Badger]

And the 6800GS also performs near par, if not better than the 6800GT, even without another pipe quad.

 

A lot of that is from a better design, methinks. More effecient.