[SOLVED] MSI B550 M.2 Slots and PCI-E combo

Jan 4, 2022
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Motherboard: MSI B550 Tomahawk

I currently have 2 Gen3 M.2 NVMe SSD in both M.2 Slots in the motherboard however I'd like to expand the storage using PCI-E to M.2 adaptor.

GPU in PCI_E1 covers the PCI_E2 and I have a wifi/bt card on PCI_E4.

I'd like to know if I could use the adapter on PCI_E3 and maintain performance.
But seeing the combination table on the manual(page 29 https://download.msi.com/archive/mnu_exe/mb/E7C91v2.2.pdf),
it seems like it won't support it?


Would it help if I got rid of the wifi card and keep the adapter in PCI_E3?
I have wired internet connection, wifi/bt card is just for convenience to control PC using my phone/tablet.
 
I was hoping to get some direction and options before I start panicking after going through the process of installing everything.
There is no way for installing three NVME x4 drives (at full x4 performance) into your motherboard.
You'll have to replace one of your 1TB drives with 2TB model.
For third drive you can use external USB NVME enclosure.


If you're ok with limited performance, then you could use PCIE riser cable,
connect it to PCIE x1 slot (PCIE_E4) and install PCIE M.2 adapter in there.
You'll get 4 times reduced nvme drive performance though.

Note riser cable PCIE slot connector is with open end. Larger than x1 card can be inserted there.
 
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Lutfij

Titan
Moderator
Welcome to the forums, newcomer!

What processor did you pair with the motherboard listed above? You might also want to parse the make and model or a link to the PCIe M.2 adapter. If you must expand on your storage without compromising on lanes, might want to look at 2.5" SATA based SSD's. Speaking of SSD's why not opt for higher capacity M.2 SSD's in place of what you already have(I'm assuming you didn't opt for budget M.2 SSD's, although make and models of the M.2 drives would help)?
 
Jan 4, 2022
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Welcome to the forums, newcomer!

What processor did you pair with the motherboard listed above? You might also want to parse the make and model or a link to the PCIe M.2 adapter. If you must expand on your storage without compromising on lanes, might want to look at 2.5" SATA based SSD's. Speaking of SSD's why not opt for higher capacity M.2 SSD's in place of what you already have(I'm assuming you didn't opt for budget M.2 SSD's, although make and models of the M.2 drives would help)?
I have a Ryzen 5600X and am using WD SN750 1TB on both M.2. slots. Just ordered one more but this time a 2TB one.

I was naive when I first built my system, thought 1TB was enough for my use... Then after a few months, with 200GB space remaining, I got another 1TB thinking, "it wasn't that bad with just 1TB, another 1TB should be enough." and now I've got 200GB remaining in that one too.
I've learnt from my experience so I've decided to just buy 2TB version of the same SSD...
I just wanna keep using M.2 as SATA is getting outdated and the speed difference is quite substantial. Also don't want my current SSD to go to waste :/

M.2 NVMe SSD's are ridiculously priced on any other volume more than 1TB so that also led to me just buying 1TB each time before.

The adaptor I've got is RevuAhn EX2M2. Unfortunately, it doesn't fit PCIe x1, only PCIe x4~x16.

Currently I'm waiting for the SSD to be delivered which will take few weeks. I was hoping to get some direction and options before I start panicking after going through the process of installing everything.
 
I was hoping to get some direction and options before I start panicking after going through the process of installing everything.
There is no way for installing three NVME x4 drives (at full x4 performance) into your motherboard.
You'll have to replace one of your 1TB drives with 2TB model.
For third drive you can use external USB NVME enclosure.


If you're ok with limited performance, then you could use PCIE riser cable,
connect it to PCIE x1 slot (PCIE_E4) and install PCIE M.2 adapter in there.
You'll get 4 times reduced nvme drive performance though.

Note riser cable PCIE slot connector is with open end. Larger than x1 card can be inserted there.
 
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I'd like to know if I could use the adapter on PCI_E3 and maintain performance.
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It certainly looks like like you'll only get X2 bandwidth if you leave the WiFi adapter in PCI_E4. Remove it and PCI_E3 reverts to full X4 bandwidth. But you lose M.2_2 entirely each way. FWIW...it should be Gen 3 either way though since the lanes originate at the PCH.

In practice, your work needs to involve frequent transfers of very large contiguous files, either to the same drive or one of equal performance capability, to really appreciate any difference in actual performance. Windows doesn't normally work that way. I'd just use a good SATA SSD drive. Or two. Or four.
 
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natcha12

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Sep 1, 2015
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You are wasting your PCIe3 x1 slot on wifi or ethernet. That slot can do 1 gigaBYTE, whereas your wifi might be ok using USB 2.0 dongle at 40MB/480Mb speeds.

Sure, it's not gonna be as fast as your other SSD if you put one in the pcie slot, but if you don't want to waste them, just make sure to put the smallest capacity or least used one there so it has the least impact.

With your 2 SSD currently in pcie mode, pcie2 and 3 re turned off. You only have the bottom one and your gpu active. You can't use them even if you could physically reach them, not enough lanes.

FYI, you could also keep current setup and use SATA ssd which might be a bit easier to setup, but that would be 6Gb vs that pcie slot at 8Gb.
 
There is no way for installing three NVME x4 drives (at full x4 performance) into your motherboard.
Actually - there is one way for installing more than two x4 M.2 NVME drives.
You'd have to give up graphics card being installed in PCIE x16 slot.

If you move graphics card to second PCIE x16 slot (x4 mode) - PCIE_E3, then
you could install PCIE x16 M.2 adapter in first PCIE x16 slot (PCIE_E1).
This adapter supports up to four M.2 NVME drives.
Note - M2_2 slot can not be used in this configuration, but you can use M2_1 slot plus four drives on the adapter.
So - five M.2 NVME drives total.

 
Actually - there is one way for installing more than two x4 M.2 NVME drives.
You'd have to give up graphics card being installed in PCIE x16 slot.

If you move graphics card to second PCIE x16 slot (x4 mode), then
you could install PCIE x16 M.2 adapter in first PCIE x16 slot (PCIE_E1).
This adapter supports up to four M.2 NVME drives.
Note - M2_2 slot can not be used in this configuration, but you can use M2_1 slot plus four drives on the adapter.
So - five M.2 NVME drives total.

It might work, no doubt. But PCIe x4 has been shown to significantly cripple GPU performance. And it's gen 3 too, so gen 4 bandwidth won't help if GPU performance still matters for gaming.

But if this is an effort to shoe horn a desktop gaming computer into an HEDT workstation role then true super high speed data throughput performance might just be more more important than GPU performance.
 
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natcha12

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Sep 1, 2015
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Actually - there is one way for installing more than two x4 M.2 NVME drives.
You'd have to give up graphics card being installed in PCIE x16 slot.

If you move graphics card to second PCIE x16 slot (x4 mode) - PCIE_E3, then
you could install PCIE x16 M.2 adapter in first PCIE x16 slot (PCIE_E1).
This adapter supports up to four M.2 NVME drives.
Note - M2_2 slot can not be used in this configuration, but you can use M2_1 slot plus four drives on the adapter.
So - five M.2 NVME drives total.

Possible. But gpu would be in 3.0 x4, not 4.0, plus he would have a half speed disabledm2 slot, but as long as all were installed in the top pcie, might be workable

 
Jan 4, 2022
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It certainly looks like like you'll only get X2 bandwidth if you leave the WiFi adapter in PCI_E4. Remove it and PCI_E3 reverts to full X4 bandwidth. But you lose M.2_2 entirely each way. FWIW...it should be Gen 3 either way though since the lanes originate at the PCH.

In practice, your work needs to involve frequent transfers of very large contiguous files, either to the same drive or one of equal performance capability, to really appreciate any difference in actual performance. Windows doesn't normally work that way. I'd just use a good SATA SSD drive. Or two. Or four.
It's just for games and videos. Are you suggesting if I kept PCI_E4 free, I could use PCI_E3 and M2_2?
I bought the M.2 SSD and PCIE adapter for the superior speed it provides compared to SATA.. If that doesn't doesn't work out, I'll just have to live with what I get.
 
Jan 4, 2022
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You are wasting your PCIe3 x1 slot on wifi or ethernet. That slot can do 1 gigaBYTE, whereas your wifi might be ok using USB 2.0 dongle at 40MB/480Mb speeds.

Sure, it's not gonna be as fast as your other SSD if you put one in the pcie slot, but if you don't want to waste them, just make sure to put the smallest capacity or least used one there so it has the least impact.

With your 2 SSD currently in pcie mode, pcie2 and 3 re turned off. You only have the bottom one and your gpu active. You can't use them even if you could physically reach them, not enough lanes.

FYI, you could also keep current setup and use SATA ssd which might be a bit easier to setup, but that would be 6Gb vs that pcie slot at 8Gb.
True, I even have wired connection and the card is just there for convenience on rare occasion I have to use my phone connected on the same wifi to control my PC from far or connect to bt speakers.. Was thinking of getting a wireless touchpad+keyboard combo to replace that need anyways.
I just up and bought another adapter which supports PCIE X1 and since SSD is already on its way, I'm just gonna have to live with hindered speed(which I doubt I will notice anyways)
 
Jan 4, 2022
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Games and videos won't benefit from that, vs a SATA III SSD.
Yeah you're right, although one of the reason for buying M.2 SSD with adapter is for... easier install when it comes down to it. I'm just lazy and I throw an unnecessary amount of money into my problems(which are not even problems to the majority of the people).
 
It's just for games and videos. Are you suggesting if I kept PCI_E4 free, I could use PCI_E3 and M2_2?
...
The chart MSI provides is confusing because nothing explains the difference between a "-" for unavailable and an "X" for not present so you'd have to test for that. But it is clear that if you kept PCI_E3 free you could use PCI_E4 and M2_2.

But the bottom line is you'll get no benefit from an NVME's sequential transfer speeds for videos and games since Windows just does not work that way. A good SATA SSD will do just as well since they provide the same random access performance benefits. You should have at least 4 SATA ports available on that board, that makes this whole exercise pretty much pointless.
 

natcha12

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Sep 1, 2015
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True, I even have wired connection and the card is just there for convenience on rare occasion I have to use my phone connected on the same wifi to control my PC from far or connect to bt speakers.. Was thinking of getting a wireless touchpad+keyboard combo to replace that need anyways.
If your case is plastic surrounded, not fully metal, you can get away with using one of these;


That'll keep the bluetooth/wifi dongle inside the case, decent enough for BT KB/M. Plus you keep the external ports clean and clear
 

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