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*** AMD "Zen" thread (inc AM4/APU discussion) ***

DragonQ said:
On X370/XZ470, the first M.2 slot is PCIe 3.0 x4. The second M.2 slot will be PCIe 2.0 and it will share bandwidth with something. Usually one or more PCIe slots or SATA ports, but it depends on the motherboard - you need to read their user manuals to find out.

I believe the Crosshair VI is the only X370 board to have a secondary M.2 slot that is PCIe 3.0 x4 and that's because it shares bandwidth with the second GPU slot. So as long as you're only planning on ever running one GPU, that board would give you full M.2 speeds for both drives. There may be X470 boards that do this also.
Click to expand...

I think ASUS Crosshair VI and VII are the only boards that do this configurations when doing my research for boards back then, well in the premium line-up of boards anyway. I am not sure in the mid section and lower tier priced boards.

if you want lots of Nvme drives just pick up a cheapish X399 board and a 1900x cost a little more but you get much more PCI lanes so can connect numerous devices without speed drop.
 
Crosshair VI has only one m2 slot, there is Crosshair VI extreme which has 2 slots. Crosshair VII is to get if you want two m2, at full speed.
 
Is anyone running a 2600x using pbo overclock on x470 hero? Reliably does 4.3 at 1.4v? I was just looking at some cb results and with 3400 ram it's possible to hit 182 single core which is pretty impressive for the cost. High 170s with easier 3200 no doubt. Tempted given the drop in upgrade on zen2 plus the fact you can do board and chip for less than 9700k.

156 on my current i7 and AC is showing my cpus age with a bottle neck.
 
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pastymuncher said:
I have a question. I have been tasked with building a pc for someone and after a good chat persuaded him to go down the AMD Ryzen route. He has one particular requirement though and wants to run a pair of NVME drives. I believe if you run a pair of NVME drives on the mainstream Intel platform (Z370/Z390) then the gpu would be dropped to 8x pci-e lanes. Is this the same with Ryzen or does AMD do things differently on AM4?
Click to expand...

Tons of great info about X470 above, but IMHO X399 sounds like the platform for you.

Built a render/editing machibe on X399 and a 1900X and it is so impressive. Didn't need 16 cores, but the IO bandwidth was essential: NVMe RAID scratch drive, RAID6 HDDs for fast bulk storage. Big memory pool.

Flogged the poor thing, split it onto two+ hardcore IO tasks, processing tasks, whatever. It just proceeds without stutter or judder or freezing, unbelievable.
 
pastymuncher said:
I have a question. I have been tasked with building a pc for someone and after a good chat persuaded him to go down the AMD Ryzen route. He has one particular requirement though and wants to run a pair of NVME drives. I believe if you run a pair of NVME drives on the mainstream Intel platform (Z370/Z390) then the gpu would be dropped to 8x pci-e lanes. Is this the same with Ryzen or does AMD do things differently on AM4?
Click to expand...

Each M.2/U2 NVMe capable drive requires a full 4x PCI-E 3.0 lanes to ensure you allow full throughput for the drive if it is a modern fast drive like a 970 Evo. Z370/Z390 both have 16 PCI-E 3.0 lanes directly from the CPU, which can be configured as 16x or 8x/8x or 8x/4x/4x, they also have 24 lanes from the PCH, but that is multiplexed, and not dedicated so anything connect back to it shares the DMI 3.0 link which is effectively only a 4x PCI-E link. Things that share the DMI 3.0 link are, SATA/USB 3.0/3.1/Ethernet as far as I know, unless you configure the board a 8x/4x/4x you can't get M.2 connected directly to the CPU without going via the DMI 3.0 channels.

It's very slightly different with AM4, and the X470 platform but ultimately you can't run two NVMe drives at full speed if you want a PCI-E slot running at 16x.

I've spent a lot of time developing system that utilise highend NVMe storage arrays, and multi-drive configurations, which is why EPYC and Threadripper have been such a blessing. I'm afraid that until PCI-E 4.0 makes it to the normal desktop space, there isn't much hope of running 2+ drives at full speed, unless you sacrifice the 16x GPU slot which shouldn't be an issue in most cases to be fair.
 
Journey said:
Each M.2/U2 NVMe capable drive requires a full 4x PCI-E 3.0 lanes to ensure you allow full throughput for the drive if it is a modern fast drive like a 970 Evo. Z370/Z390 both have 16 PCI-E 3.0 lanes directly from the CPU, which can be configured as 16x or 8x/8x or 8x/4x/4x, they also have 24 lanes from the PCH, but that is multiplexed, and not dedicated so anything connect back to it shares the DMI 3.0 link which is effectively only a 4x PCI-E link. Things that share the DMI 3.0 link are, SATA/USB 3.0/3.1/Ethernet as far as I know, unless you configure the board a 8x/4x/4x you can't get M.2 connected directly to the CPU without going via the DMI 3.0 channels.

It's very slightly different with AM4, and the X470 platform but ultimately you can't run two NVMe drives at full speed if you want a PCI-E slot running at 16x.

I've spent a lot of time developing system that utilise highend NVMe storage arrays, and multi-drive configurations, which is why EPYC and Threadripper have been such a blessing. I'm afraid that until PCI-E 4.0 makes it to the normal desktop space, there isn't much hope of running 2+ drives at full speed, unless you sacrifice the 16x GPU slot which shouldn't be an issue in most cases to be fair.
Click to expand...
You can with crosshair VII. Like someone said it slows down second pcie slot which makes it possible for two x4 m2 and x16 gpu. The only board x470 designed like this.
 
haszek said:
You can with crosshair VII. Like someone said it slows down second pcie slot which makes it possible for two x4 m2 and x16 gpu. The only board x470 designed like this.
Click to expand...

I'll quote myself "It's very slightly different with AM4, and the X470 platform but ultimately you can't run two NVMe drives at full speed if you want a PCI-E slot running at 16x."
 
haszek said:
?? Which is incorrect because you can?
Click to expand...

AMD Ryzen™ 2nd Generation/ Ryzen™ 1st Generation Processors
2 x PCIe 3.0/2.0 x16 (x16 or dual x8) *2
*2 The PCIE_x8/x4_2 slot shares bandwidth with the M.2_2 slot.

You have to slow the PCI-E 16x slots to 8x, and then use four of the lanes of the second slot to use the second M.2 port as NVMe, there is no full speed 16x slot left after you do this.
 
What that’s got to do with crosshair VII being designed differently?

Let me quote myself "You can with crosshair VII. Like someone said it slows down second pcie slot which makes it possible for two x4 m2 and x16 gpu. The only board x470 designed like this."
 
Journey said:
AMD Ryzen™ 2nd Generation/ Ryzen™ 1st Generation Processors
2 x PCIe 3.0/2.0 x16 (x16 or dual x8) *2
*2 The PCIE_x8/x4_2 slot shares bandwidth with the M.2_2 slot.

You have to slow the PCI-E 16x slots to 8x, and then use four of the lanes of the second slot to use the second M.2 port as NVMe, there is no full speed 16x slot left after you do this.
Click to expand...

This is wrong. The configuration is PCI-E 3.0 X16 occupied + M.2 slot 1 occupied with all the speed available and M.2 slot 2 occupied with all the speed available.
If you go for a Crossfire, then your second GPU will run at PCI-E 3.0 x4. While the M.2 slots will maintain their full speed.
 
haszek said:
What that’s got to do with crosshair VII being designed differently?

Let me quote myself "You can with crosshair VII. Like someone said it slows down second pcie slot which makes it possible for two x4 m2 and x16 gpu. The only board x470 designed like this."
Click to expand...

That data is from Asus specifications, why are you arguing? When was the last time you built one of these systems? You CANNOT run the 16x slot (either of them) at 16x speed with two NVME M.2 drives installed.

UXOfGZ3.jpg
 
Journey said:
That data is from Asus specifications, why are you arguing? When was the last time you built one of these systems? You CANNOT run the 16x slot (either of them) at 16x speed with two NVME M.2 drives installed.

UXOfGZ3.jpg
Click to expand...
And again You quoted some generic table

"The PCIE_x8/x4_2 slot shares bandwidth with the M.2_2 slot." Which is from the manual. But you are right, you built more systems than anybody else so you must be right.
 
haszek said:
And again You quoted some generic table

"The PCIE_x8/x4_2 slot shares bandwidth with the M.2_2 slot." Which is from the manual. But you are right, you built more systems than anybody else so you must be right.
Click to expand...

Generic table, from the Asus manual that I just uploaded for you. Sheesh.

EDIT: IN fact here's a blooming link to the whole manual so you can find the 'generic' table yourself.
https://dlcdnets.asus.com/pub/ASUS/...HERO/E13835_ROG_CROSSHAIR_VII_HERO_UM_WEB.pdf
 
Journey said:
That data is from Asus specifications, why are you arguing? When was the last time you built one of these systems? You CANNOT run the 16x slot (either of them) at 16x speed with two NVME M.2 drives installed.

UXOfGZ3.jpg
Click to expand...

Ryzen has 24 lanes, the above table shows available only 20 of them??
 
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