AMD Radeon RDNA2 Navi (RX 6500, 6600, 6700, 6800, 6900 XT)

Is there any indication which window sizes (PCIe BAR Size) are supported by GCN and if these were reconfigurable after booting?

ROCm drivers support BAR Size of >4 GB at least on GFX8 (Polaris GCN4) and GFX9 (Vega GCN5), but these are the only two officially supported GPU architectures in ROCm so far, with limited unofficial support for GFX7 (Hawaii GCN2).

Any power-of-two up to the max supported by the PCIE spec. AMD GPUs going at least as far back as GCN1 (GFX6) support both 64-bit BARs and BAR resizing, so > 4GB is no problem.

This type of driver-assisted coherence is just a fallback which incurs significant overhead. Truely heterogeneous Unified Memory Architecture (UMA) is only possible with AMD APUs or supercomputer systems like the NVidia DGX-2 and the upcoming HP/Cray El Capitan, since they use proprietary protocols (Infinity Fabric / NVLink) that support hardware cache coherence with atomic memory access.
There's really not a lot of overhead in flushing AMD's HDP cache on each command buffer submission, unless maybe the app is doing something silly like submitting a separate command buffer for every draw/dispatch call instead of building up a big buffer. So yes it is some amount of overhead, but that overhead is the same no matter what size the BAR is since AMD's drivers unconditionally do the flush on every submission (at least that was the case the last time I looked into the kernel mode driver code.) I'm not sure how they could get away with not flushing, because the driver can't know if the app wrote into a mapped portion of the BAR prior to the submission.
 
It surprises me since the game doesn't have really that much graphics. So I really don't know where all that space is going for.
I'm almost certain they are just "allocating" 12GB of RAM.

I bet it runs absolutely fine on 30 and 20 series GPUs.
 
Higher res textures and more textures i'd assume.

I mean, it's what they just said. Assumedly they didn't get a chance to port to Direct Storage yet, I don't think UE4 even has that capability right now, and wanting to support as many PC players as possible, chose to just fill VRAM a bunch instead of requiring a PCI Express 4.0 SSD speeds.

The math isn't hard, they're claiming around 16x higher texel density than standard games today. While you can drop mips quickly that's still a lot and they're just packing it into RAM.
 
I mean, it's what they just said. Assumedly they didn't get a chance to port to Direct Storage yet, I don't think UE4 even has that capability right now, and wanting to support as many PC players as possible, chose to just fill VRAM a bunch instead of requiring a PCI Express 4.0 SSD speeds.

The math isn't hard, they're claiming around 16x higher texel density than standard games today. While you can drop mips quickly that's still a lot and they're just packing it into RAM.

its why your going to want more than 8 or 10 gigs of ram if you want to play at 4k.
 
AMD Confirms RX 6000 Series Will Support Existing Ray Tracing Titles

https://adoredtv.com/amd-confirms-rx-6000-series-will-support-existing-ray-tracing-titles/


AMD Marketing said:
AMD will support all ray tracing titles using industry-based standards, including the Microsoft DXR API and the upcoming Vulkan raytracing API. Games making of use of proprietary raytracing APIs and extensions will not be supported.

Looks like there are games where it won't work, depending on the amount of TWIMTBP-infection they have.
 
I still hope they can support quake 2 rtx. It's based on a custom vulkan stuff, right ? They can work with devs on that. I hope for them thaht CP2077 is using DXR, so they can support it too.
 
Stating the obvious, did someone actually think they wouldn't? o_O

I still hope they can support quake 2 rtx. It's based on a custom vulkan stuff, right ? They can work with devs on that. I hope for them thaht CP2077 is using DXR, so they can support it too.
All DX12 RT titles are using DXR, that includes CP2077.
 
I still hope they can support quake 2 rtx. It's based on a custom vulkan stuff, right ? They can work with devs on that. I hope for them thaht CP2077 is using DXR, so they can support it too.

Quake 2 RTX uses a proprietary vendor extension so it'll never work on AMD HW currently as is but thankfully since the original game engine was released under a GPL license, the source code is totally available in public for every modified fork of the engine itself so if anyone really wanted to implement a version using cross vendor raytracing extensions it can be done ...
 
eTeknix leaked a new bench on Facebook. I don't see how anyone can argue against this, it's clear AMD is way ahead.
123302421_3568149533244012_1345075429499769440_o.jpg

I was thinking of maybe purchasing an RX 6900XT, but come to think of it, the last desktop graphics card I bought was an HD 6950, and I'd rather avoid downgrading by 50. Guess I'll wait for the 7900XT.
 
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