AMD: Navi Speculation, Rumours and Discussion [2019-2020]

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anexanhume said:
I think so. AMD had a patent on variable wavefront sizing.
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So, can they do that fully transparent to software?
Intel also has variable wavefronts (8, 16, or 32 wide) since forever. But afaict, it actually adds quite some complexity to drivers - shaders need to be compiled explicitly for each size and actually even look rather different (although I'm aware the differences are mostly due to the explicit region-based register addressing).
 
beside other specific design, most glaring changes with Navi is that AMD practically doubled most of fixed function units while shaders count increased only marginally, from 36 - 40 CU.

no Ray Tracing mention or Primitive Shader though....
 
Nemo said:
So Navi has 512Kb L1? :oops:
Vega10 has 16Kb L1.
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I believe it's just sum of L1 cache of all units inside of chip

amd_gcn_CU.png


BTW: does NAVI support RPM ? Does it support HBCC ?
 
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Nemo said:
So Navi has 512Kb L1? :oops:
Vega10 has 16Kb L1.
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The 16kB L1 of Vega 10 are per CU, this one appears to be a per-chip number (though is that really kb and not kB?). Doesn't fit the number of CUs though, maybe that's per SE (so, 4x128kB maybe), with the per-CU cache now dubbed L0?
Guesses, guesses...
 
There's also a 50th anniversary 5700XT that has higher clocks (up to 1980MHz boost, shame they couldn't push to 2GHz just for the bragging rights), and sells directly by AMD for $500.
 
DavidGraham said:
Ray Tracing is to come in RDNA 2, which means next navi generation.

https://twitter.com/x/status/1138169314186543106
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I guess that would be where the rumors of "Full" Navi coming next year comes from.

Not that we'll ever hear or see anything. But would be fascinating to know what went wrong or what trials and tribulations they faced with Navi as full Navi was supposed to launch in 2018.

Regards,
SB
 
Confirmed by Anand: No RT (coming in RDNA 2), and no VRS (also for RDNA 2?).

avi does not include any hardware ray tracing support, nor does it support variable rate pixel shading. AMD is aware of the demands for these, and hardware support for ray tracing is in their roadmap for RDNA 2 (the architecture formally known as “Next Gen”). But none of that is present here.
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Primitive Shaders is also active this time.

The one exception to all of this is the primitive shader. Vega’s most infamous feature is back, and better still it’s enabled this time. The primitive shader is compiler controlled, and thanks to some hardware changes to make it more useful, it now makes sense for AMD to turn it on for gaming. Vega’s primitive shader, though fully hardware functional, was difficult to get a real-world performance boost from, and as a result AMD never exposed it on Vega.
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https://www.anandtech.com/show/14528/amd-announces-radeon-rx-5700-xt-rx-5700-series/2
 
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