does X470 support two nvme and one GPU?

[Nine Iron]

Considering a move to AMD Ryzen but I don't know if it will support the following:

1 x graphics card (8x is fine)
2 x nvme SSD

My current Z370 will do 1x8 + 2x4, but I can't work out whether X470/Ryzen 2 combo will do the same. I gather that some lanes go straight to the CPU and others go via the chipset - can anybody clarify?

Many thanks,

M.

 

[grec]

Ryzen CPUs have x16 PCIe3 lanes for graphics/non-M.2 expansion slots, Ryzen APUs (G models with built in graphics) halves that to x8.

Ryzen has a further dedicated x4 PCIe3 lanes dedicated to an NVMe SSD straight from the CPU, I believe if you want two NVMe SSDs the second generally uses PCIe3 x2 or PCIe2 x4 (Both roughly same performance wise), often this will be tapped off one of the smaller extra PCIe slots on the motherboard, or it'll have a separate chip kinda like a PLX to handle the lanes, either way you should see any real world performance regressions on the M.2 2nd slot. So yep, many boards will allow a GPU and two NVMe SSDs all at full speed.

Under the hood there's essentially two chipsets, with both the AM4 CPUs internal chipset & the motherboards external chipset offering PCIe lanes for connection, which is a total of x20 PCIe3 (Technically x24 as x4 lanes are reserved for the ex chipset to communicate with the internal one) and x8 PCIe2 for X470 iirc, but how they get implemented varies from board to board, & sometimes you'll see manufacturers use chips to split PCIe3 lanes into double the amount in PCIe2 lanes or vice versa..

 

[tinytomlogan]

Your Z370 wires the NVME to the chipset so your graphics is on 16x and each of your nvme get 4x each

 

[Nine Iron]

So with the AMD it's some going to the CPU directly and some going to/via the chipset? As long as I get the same performance from all three components when I move from the Z370, that's all I'm after.

 

[robbiec]

Asus Crosshair Vii does. Running dual NVMe drives reporting X4 and a Vega 64 reporting X16

 

[grec]

Yep sorry, you will get the same performance after moving to Z370.
As robbie says, some boards allow a full x4 PCIe3 to both M.2 slots, with the Crosshair he has it does this by using half the lanes traditionally reserved for the 2nd (x8) GPU slot, so everything will be at full lanes on a single GPU system. Not all boards use this system but pretty much every board has a setup that will work more or less just as well as any other outside of synethetic benchmarks for specific stuff.

 

[Nine Iron]

Update - ended up going with a B450 with two nvme slots.

The arrangement is 8/4/4 at PCI-e 3.0. Graphics card at 8x suffers absolutely no performance penalty and both my M.2 drives get full speed.

Result - no need to go to Threadripper!

 

[robbiec]

Good job. I refreshed my NVMe's to a couple of 970 Evo Pluses during the week and on a fresh Win10 build getting this:

As you say, limits the need for Threadripper in normal service.