Nvidia Ampere Discussion [2020-05-14]
- Thread starter Man from Atlantis
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Every IHV supports this. All you need to have is a support of that optional feature in HW (PCIe controller) and SW
The burning question is why is it only being enabled now?
D
Deleted member 2197
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Wonder if they will "trickle down" support to non-Ampere cards? Since my X-99 MB has a toggle to enable it, seems not to require pcie-4 or Ampere cards.
Probably not a whole lot of real world benefit before, with lesser anounts of VRAM? But most importantly, AMD wasn’t lighting a fire under Nvidias rear. Now every frame counts.
Man from Atlantis
Veteran
I could see this might be happening because of a public backlash when AMD announced no Zen3 support for X470/B450 boards.
D
Deleted member 2197
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Curious if the benefits from using a feature like SAM would be included if talking about IPC gains, or is considered a separate metric?
That's great news, hopefully this becomes more widespread and we see some really gains from it. Once it becomes the standard rather than the exception game developers can start targeting it and in some ways the PC with its separate components can take advantage of something akin to a UMA.
Does anyone know if GPU's can read directly from system memory in the same way? I *think* that's what HBCC allowed but you had to manually set a potion of the system memory to be used as VRAM.
That doesn’t explain why AMD didn’t enable it earlier. They certainly needed the performance.
To me, it looks like they've already enabled it on driver level for DX12 games on current GPUs.
It would be weird not to do it since host addressable video memory has been available in Vulkan for years and both NVIDIA and AMD supported it for quite a while (256 MBs though, but this might be enought to store hot descriptors/constants/other stuff which changes on frame to frame basis and is hard to cache on GPU, especially with some devs' love).
I see RX 5700 XT being able to compete with RTX 2080 in some recent titles like Valhalla in 1440p and below, while still being much slower in 4K and it's not the only example.
It would be nice if somebody tested this title with the most recent driver vs year old driver so that we can verify whether there is something in recent drivers, which can boost performance a lot in titles like Valhalla.
That's exactly how it's done today, command processor in GPU reads everything from host memory.
In Vulkan, a dev can push constants/etc to GPU's video memory so that it's faster to read them on GPU == less overhead due to latencies when there are tons of descriptors/constants/etc
Rootax
Veteran
Maybe not worth the driver work needed ? I mean, some games are not 100% stable with HBCC on, while perfectly fine withtout it (ffxv come in mind for me). So I guess they didn't want to check if this was working ok with older gpus ?
That 256MB is always supported AFAIK no matter what API or GPU, the difference is that now that 256MB can be turned into however many gigabytes there is VRAM on each particular card
Frenetic Pony
Veteran
Sebbi's been on a tear lately with the advice and explanations. Love it and love seeing RBAR as an open standard as compared to smart access memory. Really need one standard across all platforms, hopefully looking as much like consoles as possible as well, to reduce the amount of individual platform support that's needed.
Jawed
Legend
Why do you think SAM is not RBAR?
You would think at least more tech savvy people on this forum knew that SAM is just how AMD calls it's RBAR implementation on Windows platform. I mean there was literally a video posted right after announcement where Frank Azor explains in detail how it works.
If Nvidia can confuse people with RTX it’s only fair that AMD can do the same with SAM.