ethomaz said:
No. + PS3 GPU (RSX) have direct access to the GDDR3 @ 22.4 GB/s. That's it... when the RSX is accesing the XDR it uses the 20 GB/s of the 25.5 GB/s (read) or 14 GB/s (write) bandwidth of the Cell... it is not a direct acess... it need to use the Cell to access the XDR. About the eDRAM... MS used it to framebuffer and apply post-processing filters... 10MB is enoght to 720p framebuffer. The eSRAM in Xbone is not only for framebuffer and post-processing filters... so the DMEs are needed and all the bus access... the first time MS needs to avoid the low bandwidth using the eSRAM... in 360 the 22.4 GB/s bandwidth was enough. PS3 and 360 have both the same bandwidth for GPU... the difference is that in 360 the GPU can direct access all the 512MB RAM and on PS3 the GPU can direct access only 256MB of RAM... when the PS3 GPU try to access the other 256MB RAM it is slow and cause all the issues with games not progammed to work with that slow bandwidth. |
Absolutely FALSE.
PS3 GPU as you point out, whether going through Cell or not, accessed XDR and GDDR at one.
In fact, this is the ONLY reason Sony even used two pools of RAM in PS3, to get double bandwidth, since 1 is simpler. Use your head!
Sony used two pools of RAM, MS used a single pool+EDRAM, to solve the same bandwidth problem. Had Sony only used one pool of RAM with no EDRAM. PS3 would have had severe bandwidth constraints, because 24 GB/s is not nearly enough to feed RSX.
Choice last gen was this:
Two pool
On pool+EDRAM
The only reason Sony used one pool+no EDRAM this gen (though they considered it, as Cerny said) was because they went to a 256 bit bus.
Last gen 256 bit bus was considered too expensive. They were forced into two 128 bit busses to two pools of RAM (PS3), or one 128 bus and EDRAM for 360.
