Asus ROG Crosshair X870E Hero - is it possible to have 2 x PCie5.0 SSD's?

MnsoonMally

MnsoonMally

MnsoonMally

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Asus ROG Crosshair X870E Hero - is it possible to have 2 x PCie5.0 SSD's, without taking lanes from the GPU?

If so, what should the configuration be? The manual seems a bit confusing to me.


*I asked this question on Tom's Hardware Forum, and got the usual nonsense from the moderators wanting to be King-Of-The-World, all while without answering the question and asking for Links/Additional info. I think the question speaks for itself.
 
The CPUs have the capacity to do that, but the motherboards: ouch goes my brain.

My understanding of this motherboard's manual is the following:
- M.2 slot 1 is ALWAYS free and never interferes with the primary 16 PCI-E lanes for the graphics.
- The use of EITHER M.2 slot 2 and M.2 slot 3 will steal 8 lanes from the graphics card.

Additional caveats:
- The second full length PCI-E slot is available ONLY if M.2 slot 3 is used (M.2 slot 2 will disable it).

The direct answer to your question is: no.
 
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Ouch! Indeed.
Theoretically, the number of PCIe5.0 lanes of the architecture support x16 for the GPU, and 2 x4 for SSD's?
M.2_1 and M.2_3 might work?
My head hurts. Probably blinded by it all, might be an idea to step back from it for a few days.
Appreciate your input.
 
MnsoonMally said:
Theoretically, the number of PCIe5.0 lanes of the architecture support x16 for the GPU, and 2 x4 for SSD's?
Click to expand...
Yes, these CPUs can support up to 8 additional lanes (2x M.2 PCIE 5.0 slots), but the manufacturer chooses how to handle that in their motherboard.

MnsoonMally said:
M.2_1 and M.2_3 might work?
Click to expand...
No, I am afraid not.

The use of either M.2_2 or M.2_3 will knock your GPU down to 8 lane.

I can't see any way around it with this motherboard.
 
I think you are correct.

This is why I asked the question, as I'm not sure it's possible. Same for Intel on their newer platform too.

I ask, as in February next year I'm going to be building a new rig, primarily for Gaming, but other production work too. If I could get a motherboard that fully supported 2 x M.2 SSD's at PCIe5.0, then I could have one for OS / Gaming, and one for Production Apps.

However, it does look like both platforms (AMD and newer-Intel) only allow for one PCIe5.0 SSD.

This is fine - it's just something I'd like to be clear on, before I invest in one platform or the other.
 
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MnsoonMally said:
If I could get a motherboard that fully supported 2 x M.2 SSD's at PCIe5.0, then I could have one for OS / Gaming, and one for Production Apps.

However, it does look like both platforms (AMD and newer-Intel) only allow for one PCIe5.0 SSD.

This is fine - it's just something I'd like to be clear on, before I invest in one platform or the other.
Click to expand...
The older Intel platform couldn't even do one, because the CPU has zero spare PCI-E lanes after graphics. The newer one, I think it only has 4x spare CPU-connected PCI-E 5.0 lanes.

Unless I'm missing something buried in the manual, the X670E Creator has 2x PCI-E 5.0 M.2 slots with no impact on graphics and it supports USB4 *.

* However, the spreadsheet you can find linked to on reddit notes that a PCIE 5.0 M.2 slot shares bandwidth with the USB4 controller :o
 
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I'd really like Motherboard manufacturers to be much clearer on their specifications, explicitly saying what can be supported, as an optimal maximum.

For example: 'This SuperDuper Motherboard supports 1 x PCIe5.0 M.2 SSD and 4 x PCIe4.0 SSD's without sharing bandwidth with other components.', in order to save us all confusion and guess-work.

Certainly, if I was a marketing director, I'd be insisting upon it.
 
The X670E boards with a single PCIE5 M2 slot seemed better to me. The 2nd and 3rd M2 slots can be populated with PCIE4 drives and mine has a 4th slot that's PCIE 3 (X670E TUF). Populating all 4 M2 slots doesn't touch the GPU lanes.

The ones with the extra PCIE5 support on slots 2 and 3 will drop the GPU of 8 lanes whatever gen drive you put in them.

On X870E the USB4 controller tends to take 4 lanes, meaning even less available.
 
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MnsoonMally said:
in order to save us all confusion and guess-work.
Click to expand...
Having to bury our heads in the manuals to figure out what these boards are capable of is definitely not a good situation.

I didn't expect the USB4 support to effectively degrade what lanes X870/X870E can offer over the previous boards.

If you don't care about USB4, I'd go for the previous gen Strix X670E-F and run your two PCIE 5.0 M.2 slots, but obviously you'd lose the option of ever running 3 of those drives.
 
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I'm happy to run the OS and Gaming drive on the single Gen5 SSD, and use a couple more Gen4 for other drives I will need (Apps, slower-games, mass-storage).

My intention was to see if this motherboard, or the architecture in general, supported 2 x Gen5 SSD slots. As then I could have had my OS/Games and Apps on separate, but fastest slots.

Seems not. No issue with Gen5/Gen4 combination, but had to check if 2 x Gen5 was possible (without taking).
 
MnsoonMally said:
Seems not. No issue with Gen5/Gen4 combination, but had to check if 2 x Gen5 was possible (without taking).
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I assume you're aware of this, but just to clarify: if you buy a board with the same M.2 slot config as the Hero (with the three PCI-E 5.0 M.2 slots) and install a gen 5 and a gen 4 drive (in the gen 5 slot), you'd still lose the lanes in that board, because the lane stealing is hardwired.
 
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Yes, I specced-up 11 motherboards in total of X870E, and made an Excel spreadsheet of what they 'contain'. In general, they contain less M.2 slots than their LGA1851 Intel counterparts - which also only offer 1 x Gen5 SSD; but multiple Gen4.

I will need a motherboard, of whichever manufacturer, to contain (at least) 1 x Gen5 and 2 x Gen4. Without sharing.
 
MnsoonMally said:
I will need a motherboard, of whichever manufacturer, to contain (at least) 1 x Gen5 and 2 x Gen4. Without sharing.
Click to expand...
That should be fairly easy, I think, but funnily enough cheaper boards are less likely to cause problems than expensive boards (because they don't try to gen5-ify everything).
 
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For Intel it is all very possible.

If I choose Intel for an LGA1851 build, it seems the MSI MEG Z890 Ace would be the one I would pick, after checking some 20+ boards, and seeing a half-dozen that would 'do the job'.

Fast CUDIMM memory, plenty of M.2 (only 1 Gen5 of course), lots of higher-end USB connectivity, with 10GB LAN too.

I looked into AMD as it's CPU's rout Intel for gaming performance; and the 9950X3D due out early next year will probably fly even faster. But gaming isn't everything I need.
 
MnsoonMally said:
I'm happy to run the OS and Gaming drive on the single Gen5 SSD, and use a couple more Gen4 for other drives I will need (Apps, slower-games, mass-storage).

My intention was to see if this motherboard, or the architecture in general, supported 2 x Gen5 SSD slots. As then I could have had my OS/Games and Apps on separate, but fastest slots.

Seems not. No issue with Gen5/Gen4 combination, but had to check if 2 x Gen5 was possible (without taking).
Click to expand...
I wouldn’t worry about PCI-e gen 5, especially for storing games and apps.

It won’t make a noticeable difference.

Just run a couple 4.0 gen drives and you’ll be fine.
 
I agree - as I understand it, while each iteration of PCIe is double the rate of before, to the human eye, it's pretty much the same.

I'll be running MSFS2020, and eventually MSFS2024, so will be putting this on the Gen5 SSD, to stop any potential for stuttering while flying.

Gen4 is fine for everything else.
 
In passing, and this kinda has nothing to do with the thread, the ROG STRIX X870E-E GAMING WIFI, has three pcie5 slots, and very unusually places them all below the CPU. To accommodate the extra sockets, they have moved the GPU down. An interesting design choice. So, if you are considering populating two, then perhaps that's one to consider. (Personally, I love the sockets NOT located under the GPU!!!!).




The only thing you have to watch is people like Gigabyte use GPU supports based on the relative position of the motherboard screws and the GPU socket - which is different for the Asus Motherboard.
 
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