Discussion in 'Frontpage news' started by SpajdrEX, Nov 21, 2020.
Win for everyone
Skip to 34:45
It doesn't do much good if they keep it artificially locked behind Zen 3. From everything I've heard, it's all down to the chipset, so anyone with an X570 should be good to go if AMD allows it.
thats cool,if only all companies would work toghether more then against each other for the money ,i think all tech would be in a better place,so its really good to see amd doing something like this
Except GPU is not connected via chipset.
except when it is?
As Astyanax said... except when it is. It depends on the board layout, but there will be separate slots for which PCIE lanes are from the CPU and which ones are from the X570 chipset... and unless my memory is completely borked, the Zen 2 chips/3K series use the same controller as the Zen 3 chips, and have PCIE4 support.
Read topic name, please. If anyone runs their modern GPUs via chipset on consumer gaming platform, they do not need smart memory access. They need new brain.
Yeah, magic PCIe slot via chipset. Check how many lanes it has. And which things get disabled moment you put anything into that slot.
4x PCIE4, same bandwidth as 8x PCIE3. You think that's not going to be enough with modern cards?
It may or may not, though the SAM feature may become not as beneficial, who knows.
My main question on this line of thinking ia this: If AMD were to make it a chipset requirement rather then a CPU requirement, or rather, "either/or", would that not be super confusing and cause issues?
"HEY! I have a 3800x on a x570 motherboard and i can't use SAM! It says i should be able to! .... You're telling i gotta pay attention to what slot i have it in???"
Just seems like a headache for the industry to me, past this generation it won't matter.
@Aura89 Either way it seems like it should be able to work on Zen 2, so PCIE4 4x possibly being a bottleneck shouldn't matter.
Your original statement:
"From everything I've heard, it's all down to the chipset, so anyone with an X570 should be good to go if AMD allows it."
No it is not. Chipset is irrelevant when All GPUs in gaming PCs run direct lines to CPU. And moving target in later part of discussion to something else is not going to change it.
It is not about something being bottleneck. It is about statement that chipset has any relevance in this.
(Well, it is as relevant as saying: You can use certain M.2 NVMe-s only on boards with X570 chipset... as if there was no M.2 slot directly connected to CPU.)
Kudos for AMD for this kinda of move, that benefits everyone.
AMD's words, they claim it's required, so yes, from what I've heard. Even if they later state they'll allow SAM for non-Zen 3 chips, they might make X570 a requirement based on the what I've been hearing them say.
The chipset provides a lot of basic functionality, most of which we can't look up in detail, it can't be irrelevant, and maybe there's something about the X570 chipset that allows BAR to work at all which is why AMD have such a boner over it? We don't know.
And not that it matters: How much do you want to bet there are a lot of people who have their video cards in the 2nd PCIE 16x slot not knowing it's running off of the chipset?
The point of the conversation is that it could probably work on combinations that are not only X570 + Zen 3. So yeah, it is relevant to this discussion.
resizable bar support isn't new, there are even some pcie gen 2 platforms that support it, the issue is that enabling support isn't consistent and varies by platform and by bios , and things like pcie hubs can interfere with enabling support,
amd is promising support on x570 because thats what they have working consistently, on the linux side of things, amd has had resizable bar support in their amdgpu kernel driver for a while, which works on various intel and amd platforms , but not all.
2nd x16 PCIe slot on AMD's platform is wired as x8 because it goes to CPU. When it is used, 1st slot has 8 lanes disabled. So slots become wired as x8 + x8.
And similar thing applies to intel's consumer platform.
I don't know what you're referring to, but on the X470 and X570 boards I've had the 2nd 16x slot runs off the chipset, not the CPU. The 1st slot could be cut down to 8x speed but if a different slot is filled, not the 2nd 16x slot.
So B550 is excluded?
Spoiler: This may help you a bit on making distinction between things wired to CPU and those wired through chipset.
Not every AMD mainboard is wired the same way.
many of them have the 16x_2 slot wired on a switch that can choose to be run on either of the controllers so they get the full 16x bandwidth if desired.
But that layout for the 470 isn't applicable to the x570 which afaik, has more lanes.
Look for the image. AM4 is AM4.