I put this as an answer to your thread elsewhere as its relevant here. Plus, there are more things at the bottom in reply to your post above.
Well, except for what's already leaked out there or what some sites have been authorized to say so far, X570 and Ryzen 3000 series CPU's are under embargo until 7/7/19. That said, I don't have any information, or not much information that's not already out there in some form. What it looks like from the block diagrams I've seen online is that X570 incorporates some type of switching technology on the back end like Intel's HSIO that allows the motherboard vendors some flexibility that they didn't have previously for configuring their motherboard features.
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This is an example of what I'm talking about. You see where it says: "Pick one". That's for motherboard manufacturers to choose from. They can decide how they want to adjust the configuration.
So, from the CPU side nothing has changed. You get 20x PCIe lanes, 4x of which are reserved for communication with the PCH. Then you have 4x dedicated USB 10Gbps ports and dedicated storage interface comprised of four PCIe lanes. These can be allocated as a single 4x NVMe slot or it can be split into two 2x NVMe slots or it can incorporate 2x SATA ports and a single 2x NVMe slot. None of the manufacturers are likely to do anything but use this for a single 4x NVMe M.2 slot. It will almost always be a type 22110 slot.
On the PCH side, we have a dedicated 8x PCIe slot and after that the choices are in the diagram. We will probably see several variations on one pick one category and the second will probably generally be allocated as SATA ports if I had to guess. Or we'll see some PCIe switches which will allow us to have slots or an extra 2x or 4x cluster of SATA ports which will be shared. That will give us a potential for 6 to 8 SATA 6Gbps ports and the last PCIe x4 lanes that will be shared with the SATA ports will almost certainly be allocated as another x4 M.2 slot. This one, potentially supporting SATA as well as PCIe devices.
From the X570 motherboards I've seen pictures of so far, I think I'm 100% spot on with the above assuming I'm reading this correctly. The motherboards all seem to have three PCIe x16 slots. Two will be allocated as x16/0 or x8/x8 with an additional x8 slot tied to the PCH. So that's an improvement, and where all the new lanes are technically going. There are also cases where we are seeing some PCIe x1 slots scattered around the expansion slot area, so that's where one o the "pick ones" are going. The second "pick one" is definitely going towards SATA and M.2 slots. The first pick one is likely also M.2 as well. I'm seeing 3x M.2 slots on most of these boards and only one of that can go to the CPU directly.
Based on what you said in the other thread, I don't think you can get what you want out of X470 or even Z390. I think you have to decide whether or not to go with X399 or X570. No one uses PLX chips anymore because they are extremely expensive and they don't improve performance, just flexibility. The reason I bring up X399 is because it will give you what you want and there are deals to be had on Threadripper 12 core and 16 core parts. Plus, in theory, you should be able to get a drop in upgrade when Threadripper 3000 series chips hit in Q4 2019. Plus, X399 is a bargain compared to the price of some of these X570 motherboards. So that's something to think about.
Yeah, since my 10Gig NIC is Gen 2 it should have more than enough bandwidth off of the 4x Gen 4 lanes going to the chipset, even with other things going at the same time.
That's not how it works. If you have a PCIe 4.0 slot and put a PCIe Gen 2.0 device in it, that slot will operate in 2.0 mode. For your controller to work the way you want it to, you need an x8 slot electrically to pass x8 PCIe Gen 2.0 data across the bus. The connectors all line up the same way. You can't suddenly get an x4 PCIe 4.0 slot that only covers half your card's physical connector to operate at full bandwidth.
I'm hoping at least one motherboard maker gives us a board where I can use 16x off of the CPU for the GPU, 4x off of the CPU for a single m.2 drive, and then have an 8x slot off of the chipset for my NIC. From what I understand this type of configuration should be possible. I just don't know how likely it will be... :/
This is where I think you are in luck. Given the above block diagram and the physical boards I've seen, I think this is actually possible and likely.
Yeah, I know this intellectually, both from past tests, and from looking at the PCIe bandwidth utilization chart in RivaTuner which I usually have installed as part of MSI Afterburner, and have open on a side window when I run games.
I just can't seem to get over the urge to have the full 16x to the GPU "just in case", primarily because everything else in my system I have some margin. On my GPU I have next to no margin. I need it to perform as fast as it possibly can or I don't get my 60fps at 3840x2160
Well, I have x16 lanes for my GPU and I can't even get 60FPS all the time at 3840x2160. There are some games like Destiny 2 where this doesn't always happen at max settings. Even so, its generally been proven that in most cases full x16 lanes of bandwidth aren't needed, even for high end GPU's. I can still understand where you are coming from here as its one of the many reasons I've stuck with HEDT platforms.
Well, the x570 supposedly has 16x PCIe lanes the motherboard vendors can use as they see fit. I hope at least one of them makes an 8x slot available off of the chipset I can stick my NIC in. I'm not concerned about the bandwidth. It's a 2x 10gigabit NIC, so we are talking 20 gigabit. Both the NIC and the PCIe lanes are full duplex, so I shouldn't have to account for that.
As I said, I think you are going to be in luck with X570. With earlier boards, this isn't ever going to happen.
The NIC is Gen 2 8x, so it is at most capable of using 4,000 MB/s out of the ~8,000 MB/s available from the 4x Gen 4 slots going from the CPU to the Chipset. This leaves ~ half of that bandwidth for the on board devices, which is probably fine. Sound probably doesn't use much, given that old sound boards were fine using 1x Gen1 slots. That and the NIC will likely never come close to this 4,000 MB/s max, due to 20Gigabit being ~ 2560 MB/s. There is likely some overhead on top of that for the protocol, but I can't imagine it would max out the full 4,000 MB/s of 8x Gen 2.
Again, this isn't how the slots work. If you stick an x8 dual 10GbE NIC into a Gen 4.0 x8 PCIe slot, all 8x lanes are going to get used. However, their speed will be downgraded and operate at Gen 2.0 bandwidth. And yes, there is overhead, but it isn't huge.
So I am keeping my fingers crossed that at least one motherboard vendor makes this kind of configuration available.
It should be possible to do, but my desires are unconventional these days though, so I probably won't get what I want.
Its certainly possible and like I said, I think you'll get close enough on X570 to make you happy.
I know. I don't understand the strong dislike people have of wires. They aren't THAT difficult to run, and if you think they are messy it is easy to hide them behind various raceways and organizers.
Wired solutions will always be faster, more reliable and more secure.
I only use wireless anything if I absolutely have to, for devices like phones where their entire purpose is that they are mobile. Anything stationary gets a dedicated wired ethernet line. I don't even use bluetooth or wireless mice and keyboards if I can help it. I'd rather everything be wired.
Typically, your going to have wires of some kind anyway. I think its about effort and some people simply not knowing how to hide the wires or being unwilling to do it in a rental space. I'd leave the bastard running around the edge of the room on the floor if that's what it took. Frequently, I did this over the years. I also learned to hide them under base boards or under the edge of the carpet. It isn't that difficult to do.