Originally posted by: Pete
Originally posted by: Ronin
Originally posted by: Pete
Originally posted by: Ronin
Biggest problem with the 360 compared to the PS3 is simple. The XBOX has a 10MB vid card buffer, which pretty much limits you to a 4X FSAA without falling into the actual RAM of the system.
The PS3, on the other hand, can utilize all 512MB of RAM as a buffer, providing a much larger space for textures and whatnot.
Naturally, this is all theoretical, but I think you're going to see the results in the visual department as an end result.
R500 has access to as much memory as RSX--actually, 10MBs more, counting the on-die 10MB buffer. And apparently R500 doesn't need to fit all the back-buffers into EDRAM at once. It can tile if need be, according to the Firingsquad ATI in Xb360 interview.
I guess we'll see after both Xb360 and PS3 are released exactly how much EDRAM helps WRT AA, when people see real games on their HDTVs.
This is the difference between what you hear, and what you see. I'm at E3 right now, and my information is based on talks with various people here.
Feel free to argue what you've heard if you want. Take what I've said for what it's worth, and disagree if you wish.
But I still don't understand what you're saying. If, as the people you talk with say, the X360 can accomodate 4xAA, do you think you need more or will get more out of the RSX at a decent framerate?
If you're saying the X360 has to fit textures into that 10MB, you're wrong--that's not what a back/stencil/Z-buffer is for. That's what the 512MB system memory (256MB allotted to each GPU) both consoles have is for.
The problem is, I don't think you know what a "buffer" is exactly. The buffer you're talking about WRT the X360's 10MB EDRAM is not used for textures. You'd think, given MS' push to standardize on 720p and AA, that they'd make sure that 10MBs would be enough. The fact that it's faster than external RAM and literally tied to the AA mechanism is apparently what will net the X360 "free" (it's probably more accurate to call it extremely efficient) AA. RSX, apparently being more like a typical PC GPU and not having any onboard RAM, may well not be as efficient with AA.
In terms of R500 having to hit main memory for buffer space, I don't know if it'll end up slower than RSX, because both will be accessing essentially identical 700MHz DDR via 128-bit buses. I would think R500, even if it had to spill its buffers over into main memory, would still have an advantage because most of its buffers were worked on in what looks to be much higher speed (and lower-latency?) EDRAM.
But, textures? Again, each console has 512MB. X360 has the GPU controlling access to the entire 512MB block. PS3 apparently has 256MB DDR for the GPU and 256MB XDR for the CPU, but the GPU can access CPU memory. I don't know if there's a penalty for the RSX using the Cell's 256MB XDR, but there probably isn't one for the R500 reaching beyond 256MB, simply because it controls all 512MB.
Again, I'm not sure what it is you intended to say. I will disagree with what I think you said, which is that the RSX has more memory to use than the R500. They both have the same amount of overall memory to work with for textures, which seems to be your main point. If your point is that either console will want to use higher than 4xAA, I'm not too sure about that. If you intended to say that R500 might end up slower with AA if it has to dip into main memory, I would think its apparent head start with EDRAM would basically keep it ahead of RSX in terms of buffer access.