Question M.2 Storage and PCIe lanes

Dec 28, 2018
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-Intel - Core i7-9700K 3.6 GHz 8-Core Processor
-Asus - ROG MAXIMUS XI HERO (WI-FI) ATX LGA1151 Motherboard
-Asus - GeForce RTX 2080 8 GB ROG Strix Gaming OC Video Card
-32gb of corsair dominator 3200 mhz
-Gen 3 Samsung 970 PRO 250GB - NVMe PCIe M.2 (operating system)

I have had a hard time getting the right answer to my questions but here it goes ...

I have no SATA plugged in and please dont reccomend SATA over m.2 because the price and minimal performance gains :)

From my understanding my chipset provides 24 PCIe lanes

-16 lanes are for the graphics card

-4 lanes are for the samsung 970 pro 250gb NVMe PCIe M.2 drive (operating system)

That leaves 4 lanes left ..

I dont want my graphics card to drop to 8 PCIe lanes

(First question)
If I wanted to put a second, Gen3 Samsung 970 evo 2tb NVMe PCIe M.2 in the second m.2 slot I shouldn't have any issues correct?
I will have used all 24 PCIe lanes?

(Second question)
With the new gen4 NVMe PCIe M.2 that have just recently come out .
I'm curious if they will still only take up 4 PCIe lanes? and will I have any compatibility issues with my set up to run Gen4 NVMe PCIe M.2 ?

For instance corsair has a new Gen4 2tb NVMe PCIe M.2 with a nice heatsink ,they are quite a bit faster and are even a bit cheaper than a Gen3 2tb Samsung 970 evo NVMe PCIe M.2

Because I will go with Gen4 over Gen3 if there's no compatibility issues

(Third question)
I know my mobo will disable some of the SATA ports to power the NVMe PCIe M.2 slots

some some of the SATA ports won't be disabled, I believe 4 of the 6 should still work

If I do add a SATA drive down the road it will most likely be a single 4tb

the research I've done suggests there's some kind of sata bus that handles them separately?
With all 24 lanes being taken up can I add a SATA drive later without compromise?

Toms hardware forums are a great place and anyone who took the time to read this is greatly appreciated , thank you for your time!
 
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Nah. Your math is wrong.
16 PCIE lanes for graphics card are connected directly to cpu (they do not use chipset PCIE lanes).

(First question)
If I wanted to put a second, Gen3 Samsung 970 evo 2tb NVMe PCIe M.2 in the second m.2 slot I shouldn't have any issues correct?
No issues.

(Second question)
With the new gen4 NVMe PCIe M.2 that have just recently come out .
I'm curious if they will still only take up 4 PCIe lanes? and will I have any compatibility issues with my set up to run Gen4 NVMe PCIe M.2 ?
Your motherboard doesn't support PCIE 4.0. Any such Gen4 SSD will run in Gen3 mode.
Compatibility issues? Unknown. Probably not.
(Third question)
I know my mobo will disable some of the SATA ports to power the NVMe PCIe M.2 slots
No. If you're using NVME M.2 drives, then no sata ports are being disabled because of this.

z390-chipset-product-brief-page-005.jpg
 
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marius_ss

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Dec 5, 2014
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well if i understand right in case i want pcie x16 for my GPUone+ m2ssd + 2 pcie ssd's I don't have really chance to find such motherboard cause i will need at least 3 slots with full dedicated speed 1x16 for gpu and 2x4 for each pci ssd and another x4 lane for M2 ssd !!!! somebody heard about such MB ?!?