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Digital Foundry's John: Been talking to developers, people will be pleasantly surprised with PS5's results

LordOfChaos

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SMH they still haven't fixed that after the facts been out there

Information (hot chips slide) about the ROPs is at 15 min. "116 Gpix/sec", he should correct it. I dont know about the TMU's sadly.

Thanks, got a correction in


This now puts the pixel rate of the PS5 in excess of the Xbox, while the Xbox retains a lead on TMUs for texture rate. Like I've been saying, I'd expect far more of a mixed bag this gen vs PS4/XBO, Pro vs One X.
 
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RoadHazard

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Thanks, got a correction in


This now puts the pixel rate of the PS5 in excess of the Xbox, while the Xbox retains a lead on TMUs for texture rate. Like I've been saying, I'd expect far more of a mixed bag this gen vs PS4/XBO, Pro vs One X.
What does "pixel rate" mean? Does it mean PS5 could actually shade more pixels per second -> higher resolution/framerate? That would be the opposite of what everyone is expecting for sure.
 

LordOfChaos

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What does "pixel rate" mean? Does it mean PS5 could actually shade more pixels per second -> higher resolution/framerate? That would be the opposite of what everyone is expecting for sure.
In a vacuum, yes, the pixel rate is how many pixels per second the GPU can render onto the screen. ROPs also deal with blending, i.e for some AA methods. But in reality this is only one step in an overall chain of graphics, you may be limited by pixel shading before that, or texturing, etc.
 

RoadHazard

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In a vacuum, yes, the pixel rate is how many pixels per second the GPU can render onto the screen. ROPs also deal with blending, i.e for some AA methods. But in reality this is only one step in an overall chain of graphics, you may be limited by pixel shading before that, or texturing, etc.
But is either of these consoles really going to be limited by rasterization rate? Both can rasterize 4K120 without issue right (?), so when would any theoretical difference ever be relevant at all? As you say, pixel shading capacity is much more likely to be the limiting factor.

Is it the case that PS5 could potentially do more layered transparencies and better AA without a performance penalty?
 
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LordOfChaos

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But is either of these consoles really going to be limited by rasterization rate? Both can rasterize 4K120 without issue right (?), so when would any theoretical difference ever be relevant at all? As you say, pixel shading capacity is much more likely to be the limiting factor.
Some AA methods would have more than native resolution x fillrate for how many operations they have to do. In all likelihood absolutely pixel shader effects and other aspects of the GPU are going to limit this before the fillrate as I mentioned, but bespoke work tailored for either console will of course lead to interesting wins and losses.
 

geordiemp

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But is either of these consoles really going to be limited by rasterization rate? Both can rasterize 4K120 without issue right (?), so when would any theoretical difference ever be relevant at all? As you say, pixel shading capacity is much more likely to be the limiting factor.

Is it the case that PS5 could potentially do more layered transparencies and better AA without a performance penalty?
It its all about what needs to be done in that frame time, a few clock cycles saved here, a missed L1 cache and 30 cycles lost there, A better shading a few won or lost etc, streaming in an asset (there is only 1 memory access at a time its shared), a cache flush, a SFS write back, it all adds up.

How does it add up, you run a benchmark, as there are 100s of things that add up.

So, what have you seen in terms of performance so far ? Any indications how things are coming together ?
 
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RoadHazard

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It its all about what needs to be done in that frame time, a few clock cycles saved here, a missed L1 cache and 30 cycles lost there, A better shading a few won or lost etc, streaming in an asset (there is only 1 memory access at a time its shared), a cache flush, a SFS write back, it all adds up.

How does it add up, you run a benchmark.

So, what have you seen in terms of performance so far ? Any inications how things are coming together ?
Of course, but I was specifically talking about PS5 potentially having superior fillrate. Whether or not that will make any practical difference.
 

geordiemp

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Of course, but I was specifically talking about PS5 potentially having superior fillrate. Whether or not that will make any practical difference.
It will positively add to the frame budget yes, as will do many other things....

Its not 1 metric, never has been.