Nvme m2 speed drops by half using adapter

Chia Plotting
1

any way to work around this? maybe some setting? mobo doesnt have m2 slot im connecting it with an adapter through 16x pcie 3.0 slot. decreased speed affects plotting a lot

2

Are you using a x1 adapter, or x4 adapter? I’m asking because if you are using a x1 adapter, the most theoretical speed you can get is 984 mbps, vs x4 adapter, you will get close to 4 gbps if it is a PCIE 3.0

3

it’s x16 adapter. pcie 3.0
im using this one ORICO M.2 NVME to PCI-E 3.0 X16 Expansion Card (PSM2-X16) - ORICO

4

ok, that should work fine. But just to make sure, does your computer have PCIE 3.0 slots? Or are they 2.0 slots? The adapter, even though it is 3.0, will still fit in 2.0 slots if that is what you have.

5

it’s confirmed pcie 3.0.
my wd sn750 only r/w 1700ish (half its max speed)
im on windows10 and already turned off the write-cache buffer flushing thing. is there any setting need to be done? maybe with bios?

6

I can’t think of any settings you would need to change. Should just be plug in play

7

Also, the drives don’t always run at their advertised max speed… if you are getting 1700, i would be happy with that.

8

Well, I just looked it up. NVME uses 4 lanes. There may be settings that are making it use only 2 lanes.
A guy having a similar problem followed these steps.

Read motherboard manual to make sure the M2_2 is Gen 3 x4 (“The Ultra M.2 Sockets (M2_1 and M2_2) support SATA3 6.0 Gb/s module and M.2 PCI Express module up to Gen3 x4 (32 Gb/s).”

Checked that I am not sharing SATA ports (* M2_2, SATA3_4 and SATA3_5 share lanes. If either one of them is in use, the others will be disabled.)

Gone into the BIOS and changed M2_2 from “Auto” to “Force M.2”

Downloaded SSD NVME driver from Samsung’s Website

Re-seated the M2

Rebooted multiple times

BIOS updated to latest

9

Alright gonna chk these BIOS settings out. Thanks

10

Yes, this is called PCI bifurcation.

There are two types of PCI nvme adapter cards:

  • cheap ones, that pass through and require BIOS settings that support PCI bifurcation – these are actually better, since it’s simple passthru

  • more expensive ones that have special chips on the PCI card which do the bifurcation for you.

1 Like
11

my mobo is biostar tb250btc pro. could only set to gen3 but no function to force m2. any clue?

12

could u please recommend some of those expensive ones?