SN750 PCIe 3.0 4x but 5 GT/S only

Hi,

I installed a SN750 and it works but the speeds are a bit lower than I expected. On closer inspection, I found that the negotiated speed to the SN750 is only 5 GT/s of the available 8 GT/s (it is on PCIe 3.0 on 4x). Has anyone experienced something similar? Any suggestions on how I can force 8 GT/s?

Thanks!

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You need to give us some more info to go on, like:

  1. What’s the make and model of your motherboard
  2. Do you use an M.2 to PCIe adapter card?
  3. Publish some benchmark test results (Crystal disk on Win, or fio on Linux (live)).
  4. What is the low level format of your SSD (512B or 4096B)?

Hi Marty,
Sure.

  1. Motherboard Model: GIGABYTE Z97P-D3
  2. Yes: https://www.amazon.co.uk/gp/product/B07RZZ3TJG
  3. See below
  4. See below

image

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I can’t add another screenshot but HWInfo is showing the Current Link Speed of 5 GTs vs Maximum Link Speed of 8 GTs for the device.

Those results are rather disappointing for such a highly spec’ed NVMe drive.

At first glance it doesn’t look like you’re running at PCIe 3.0 on 4x speeds, but rather at PCIe 2.0 4x speeds or maybe PCIe 3.0 2x …

The specs of your MB confirm my hunch.
The specs state that the PCIEX4 and PCI Express x1 slots conform to PCI Express 2.0 standard.

In which PCIe slot did you drop the M.2 to PCIe x4 card?
Unless you dropped it in the PCIEX16 slot (The PCIEX16 slot conforms to PCI Express 3.0 standard.), you’re running at PCIe 2 speeds. Then you might as well have bought a much lower spec’ed (and cheaper) NVMe drive.

If your PCIEX16 slot is unpopulated (with a video card), then drop it in there to enjoy the full power of your fast NVMe drive.

Thank you, well spotted. I assumed the x4 slot would also run at PCIe 3.0 which it apparently does not.

I have exactly similar problem.
I have motherboard ASUS TUF GAMING X570-PLUS.
There are two m.2 slots, which according to specs, are PCIE 4.0 x4.
When i put disk into m2.1, i got info, that connection is detected as PCIE 3.0 x1, and then i have trasnfers around 800 MB
When i put disk into m2.2 i got info, that connection is detected as PCIE 3.0 x4, and then i have transfers around 1700 MB (very similar to mentioned in this topic).
Sn750 is connected as “storage” drive. I have second, sata ssd disk (128 gb) which boots Windows 10.
I tried to update bios and amd chipset drivers to newest one. The same goes to sn750 - it is up to date.
What should i do to fully enjoy sn750 power? :slight_smile:
Does anyone can help me?

Can anyone help?

The SN750 is a pcie 3.0 x4 drive not pcie 4.0

Something is terribly wrong here.

According to your Mother BOARD (MB)-specs both m2_1 and m2_2 slots should be 4 lane PCIe slot, however m2_1 is a hybrid slot for PCIE 4.0/3.0 x 4 mode. Slot m2_2 is PCIE 4.0 x 4 mode only!
Your NVMe drive is PCIe Gen3 8 Gb/s, up to 4 Lanes.
Both PCIe 4.0 and PCIe 3.0 are backward and forward compatible.
But if you drop a v3 NVMe drive into an v4 PCIe slot, you’ll be operating at v3 speed.
So you can drop it in either slot.
You should be achieving around 3000 MB/s speeds at v3.
If not then either your NVMe drive has damaged PCIe lanes or your MB has damaged PCIe lanes. This could be due to dirty contacts. Clean the contacts on your drive with rubbing alcohol. Blow out your slots on the MB with air. Insert and wiggle the drive a few times.
Otherwise test your drive in another computer to determine if the drive is faulty or if your MB is faulty.

Also have a look at the following item in your BIOS:
BIOS → Advanced menu → NVMe Configuration
It should be set to 4 lanes PCIe v3 if possible.