We were talking specifically about video memory bandwidth, I showed you they were nearly identical in that regard, at just over 20GB/s. The article may have meant somewhere else. Tell me, if the video memory bandwidth is nearly identical in both how can one be better in that regard? They may have meant any number of other areas.
The vertex shader thing I do agree with, this is why every card after that has gone to unified shaders.
This is from a 2007 article, video memory usage can only have gone up since then
We were talking specifically about video memory bandwidth, I showed you they were nearly identical in that regard, at just over 20GB/s. The article may have meant somewhere else. Tell me, if the video memory bandwidth is nearly identical in both how can one be better in that regard? They may have meant any number of other areas.
Yes , both machines have a similar number for video bandwidth. But I think this quote makes the difference clear..
Quote:
The PS3 has 22.4 GB/s of GDDR3 bandwidth and 25.6 GB/s of RDRAM bandwidth for a total system bandwidth of 48 GB/s.
The Xbox 360 has 22.4 GB/s of GDDR3 bandwidth and a 256 GB/s of EDRAM bandwidth for a total of 278.4 GB/s total system bandwidth.
Why does the Xbox 360 have such an extreme amount of bandwidth? Even the simplest calculations show that a large amount of bandwidth is consumed by the frame buffer. For example, with simple color rendering and Z testing at 550 MHz the frame buffer alone requires 52.8 GB/s at 8 pixels per clock. The PS3's memory bandwidth is insufficient to maintain its GPU's peak rendering speed, even without texture and vertex fetches.
The PS3 uses Z and color compression to try to compensate for the lack of memory bandwidth. The problem with Z and color compression is that the compression breaks down quickly when rendering complex next-generation 3D scenes.
HDR, alpha-blending, and anti-aliasing require even more memory bandwidth. This is why Xbox 360 has 256 GB/s bandwidth reserved just for the frame buffer. This allows the Xbox 360 GPU to do Z testing, HDR, and alpha blended color rendering with 4X MSAA at full rate and still have the entire main bus bandwidth of 22.4 GB/s left over for textures and vertices.
You haven't addressed why you think lack of video memory isn't a problem. The graph I posted showed even games from 4 years ago could hit the capacity of these chips at close to 720P, let alone today's more demanding games.
You haven't addressed why you think lack of video memory isn't a problem. The graph I posted showed even games from 4 years ago could hit the capacity of these chips at close to 720P, let alone today's more demanding games.
At 1080p memory is a problem.
At 720p the available memory in these consoles is adequate. I, for one, am repeatedly astonished by just how much visual detail these machines can deliver.
The real problem in the videogame industry is that the production-cost of games is rising in line with Moore's law. But the revenues from the typical game is not.
At 720p the available memory in these consoles is adequate. I, for one, am repeatedly astonished by just how much visual detail these machines can deliver.
The real problem in the videogame industry is that the production-cost of games is rising in line with Moore's law. But the revenues from the typical game is not.
I know you think so, I was asking what that's based on. I showed you a four year old game hitting over 256MB.
I know you think so, I was asking what that's based on. I showed you a four year old game hitting over 256MB.
The diagram is from a PC. It seems to show the unsurprising relationship between frame buffer size and the memory required to support it. But without any supporting legends, it's hard to work out exactly how the figures are derived.
Yes games could use more memory, but that would further drive up production costs both of the consoles and the costs of game development. Personally I don't hear anyone complaining about visual quality.
My point was that on a PS3 with a large frame buffer, all of the available memory bandwidth is consumed simply servicing the frame buffer and shoving it on the screen - this occurs before the GPU gets to even draw the first polygon.
If it's okay with you, I think I have over-stated this point, and won't be addressing it again.
Comments
The vertex shader thing I do agree with, this is why every card after that has gone to unified shaders.
This is from a 2007 article, video memory usage can only have gone up since then
http://www.yougamers.com/articles/13...ly_need-page3/
We were talking specifically about video memory bandwidth, I showed you they were nearly identical in that regard, at just over 20GB/s. The article may have meant somewhere else. Tell me, if the video memory bandwidth is nearly identical in both how can one be better in that regard? They may have meant any number of other areas.
Yes , both machines have a similar number for video bandwidth. But I think this quote makes the difference clear..
The PS3 has 22.4 GB/s of GDDR3 bandwidth and 25.6 GB/s of RDRAM bandwidth for a total system bandwidth of 48 GB/s.
The Xbox 360 has 22.4 GB/s of GDDR3 bandwidth and a 256 GB/s of EDRAM bandwidth for a total of 278.4 GB/s total system bandwidth.
Why does the Xbox 360 have such an extreme amount of bandwidth? Even the simplest calculations show that a large amount of bandwidth is consumed by the frame buffer. For example, with simple color rendering and Z testing at 550 MHz the frame buffer alone requires 52.8 GB/s at 8 pixels per clock. The PS3's memory bandwidth is insufficient to maintain its GPU's peak rendering speed, even without texture and vertex fetches.
The PS3 uses Z and color compression to try to compensate for the lack of memory bandwidth. The problem with Z and color compression is that the compression breaks down quickly when rendering complex next-generation 3D scenes.
HDR, alpha-blending, and anti-aliasing require even more memory bandwidth. This is why Xbox 360 has 256 GB/s bandwidth reserved just for the frame buffer. This allows the Xbox 360 GPU to do Z testing, HDR, and alpha blended color rendering with 4X MSAA at full rate and still have the entire main bus bandwidth of 22.4 GB/s left over for textures and vertices.
C.
You haven't addressed why you think lack of video memory isn't a problem. The graph I posted showed even games from 4 years ago could hit the capacity of these chips at close to 720P, let alone today's more demanding games.
At 1080p memory is a problem.
At 720p the available memory in these consoles is adequate. I, for one, am repeatedly astonished by just how much visual detail these machines can deliver.
The real problem in the videogame industry is that the production-cost of games is rising in line with Moore's law. But the revenues from the typical game is not.
C.
At 1080p memory is a problem.
At 720p the available memory in these consoles is adequate. I, for one, am repeatedly astonished by just how much visual detail these machines can deliver.
The real problem in the videogame industry is that the production-cost of games is rising in line with Moore's law. But the revenues from the typical game is not.
I know you think so, I was asking what that's based on. I showed you a four year old game hitting over 256MB.
I know you think so, I was asking what that's based on. I showed you a four year old game hitting over 256MB.
The diagram is from a PC. It seems to show the unsurprising relationship between frame buffer size and the memory required to support it. But without any supporting legends, it's hard to work out exactly how the figures are derived.
Yes games could use more memory, but that would further drive up production costs both of the consoles and the costs of game development. Personally I don't hear anyone complaining about visual quality.
My point was that on a PS3 with a large frame buffer, all of the available memory bandwidth is consumed simply servicing the frame buffer and shoving it on the screen - this occurs before the GPU gets to even draw the first polygon.
If it's okay with you, I think I have over-stated this point, and won't be addressing it again.
C.