MP 1,1-5,1 NVMe U.2 SSD through a PCIe adapter read/write speed issues

[cidsphere]

(Cross post from r/macpro, sorry for those who already seen this post...)

Hi guys, I'm currently having read and write speed issues using an NVMe U.2 SSD through a PCIe adapter.

Using Blackmagic Disk Speed Test, I get a little more than 500MB/s write speed and around 420MB/s read speed which is too low for the kind my SSD. In comparison, the same drive and adapter gets more than 1000MB/s read/write in a linux based PC (don't know the exact figures, it's just way higher than in macOS).

I tried benchmarking while booted up in a separate drive and also while booted up directly on this drive. I also tried all the PCIe slots with no luck. The is working in 5gt/s (whatever it means ?!) in 4x mode. I initialy tried with macos HS with bootrom updated but didn’t make any changes to the speed reported by Blackmagic DST.

Here is my setup:

• cMP 4,1->5,1 with fully updated firmware running Mojave
• INTEL SSD DC P3605 1.6TB (SSDPE2ME016T4S) with firmware fully updated (RA14 I think)
• Startech PEX4SFF8639

I want to try out at some point booting up linux on the cMP and do the same benchmark and see if it’s an hardware or software issue.

But before, does anyone have a clue on what to look for ?

 

[tsialex]

While it's a PCIe 3.0 X4 device, which should get around ~1450MB/s installed in a MP5,1, it's a 2014 era NVMe 1.0 U.2 drive and almost, if not all, drives from this era have compatibilities problems with NMVe 1.3 Mac Pro EFI module.

With a 500MB/s throughput, I suspect that your drive is initialising as a PCIe 1.0 device, you can confirm/disprove this with pcietools.

Btw, you need to have at least BootROM 140.0.0.0.0 to have native NVMe support, only Mojave BootROMs have native NVMe support. High Sierra BootROMs don't have it. Read the first post MP5,1: What you have to do to upgrade to Mojave (BootROM upgrade instructions).

 

[cidsphere]

Thanks @tsialex !

With a 500MB/s throughput, I suspect that your drive is initialising as a PCIe 1.0 device, you can confirm/disprove this with pcietools.

can you help me find the pcietools you are referring to? can’t find anything related to that specifically on this forum or google.

I did upgrade the bootrom, I can even boot on the drive using mojave but would still like to reach full speed if that is possible.

 

[tsialex]

Thanks @tsialex !



can you help me find the pcietools you are referring to? can’t find anything related to that specifically on this forum or google.

I did upgrade the bootrom, I can even boot on the drive using mojave but would still like to reach full speed if that is possible.

You can install from here https://github.com/gmerlino/homebrew-pciutils

Use the MR search with setpci and Mac Pro forum, you will find various posts describing how to verify the speeds and you will find examples on how to set the speed, anyway, even if it works, you will have to do every boot.

 

[Slash-2CPU]

What’s Intel SSD utility say about lifetime usage? There’s some used OEM Oracle P3605’s around that have been used hard.