Has ATI compared the shading power of Xenos to the R520?
- Thread starter ralexand
- Start date
Here's the link that said it took a week to port:
http://www.anandtech.com/tradeshows/showdoc.aspx?i=2420&p=6
Op_Ivy on GAF took some shakey cam video of this that you can find on xboxyde.com and he said he asked the ATi rep who stated it was 30fps(due to not being optimized) also another chap talked with a rep and they said the same thing. This was all in a GAF thread if you'd like to look for it...
http://www.anandtech.com/tradeshows/showdoc.aspx?i=2420&p=6
Op_Ivy on GAF took some shakey cam video of this that you can find on xboxyde.com and he said he asked the ATi rep who stated it was 30fps(due to not being optimized) also another chap talked with a rep and they said the same thing. This was all in a GAF thread if you'd like to look for it...
Presumably the demo was CPU bound as the conversion was only made in a week from Intel to PPC. Otherwise it shows the transition to unified shaders won't be transparent which'll make their adoption for PCs kinda tricky.
Shifty Geezer said:
Errr, sorry, but WTF?
"Unified shaders" or not is transparent for a given environment such as the PC with Windows/DX; what isn't transparent in this case is the entire environment surrounding the unified shaders.
You sure Dave? I heard they were making the unified shaders out of plexiglass. :|DaveBaumann said:
That's what I thought, which is why I said it must probably be CPU limited. If it weren't the port to PPC that dropped the frame-rate from 60 to 30 fps, then it's the GPU. IF that were the case, use of unified shaders isn't transparent. With the case unified shaders SHOULD be transparent, the difference in frame rate between PC+R520 and G5+Xenos wouldn't be so vast, unless Xenos is very underpowered to R520 elsewhere, which I don't believe is the case.DaveBaumann said:
The only possible reason for Unified Shader not to be transparent is if the load balancing doesn't work too effectively without dev intervention. So if it wasn't the port to PPC that dropped the frame rate, and if it wasn't the relative shader power, the only other explanation is handling the unified shaders. That's open-ended reasoning exploring possibilities, and not a statement on the use of unified shaders.
I'll just point out what I first said...
If the load balancing was that poor then the easiest solution would be to just dedicate one of the arrays to VS work and two to PS!
However, I remian unconvinced as to where people are getting these performance figures from and we have no clue on the targets - IIRC the original Ruby for PC wasn't targeted to 1600x1200 so there is a good chance the XBOX demos was running a higher resolution than the target for the PC. The demo itself is not going to be significantly CPU intensive since it is just a cutscene and I doubt there is much for it to have to handle (e.g. no physics or collision detection etc) and unless there were performance issues for the specific CPU difference I would imagine the main performance issues, and porting time, are likely down to the assets for the scene which likely targeted at least 1GB of system RAM and possibly 512MB of local framebuffer.
However, I remian unconvinced as to where people are getting these performance figures from and we have no clue on the targets - IIRC the original Ruby for PC wasn't targeted to 1600x1200 so there is a good chance the XBOX demos was running a higher resolution than the target for the PC. The demo itself is not going to be significantly CPU intensive since it is just a cutscene and I doubt there is much for it to have to handle (e.g. no physics or collision detection etc) and unless there were performance issues for the specific CPU difference I would imagine the main performance issues, and porting time, are likely down to the assets for the scene which likely targeted at least 1GB of system RAM and possibly 512MB of local framebuffer.
I may be completely wrong on this so don't kill me. But when has a graphics card demo that complex ever ran at 60fps?? I remember when I first bought my 9800, and tried out the demos that were made for it, and even the 9700 demos, and although they all look terrific, none were 60fps. So 30fps for a R520 demo on Xenos is pretty impressive if you ask me...
