Inspiron 5770: NVMe SSD - how many PCIe lanes on M.2?

There are 2 possible causes of that bottleneck:

- Only having 2 PCIe lanes wired to the NVMe interface.  I don't know for certain if any Dell systems are wired this way, but if that's the case, that's not something that can be added via firmware; that's a hardware wiring design.

- Having 4 PCIe lanes wired to the NVMe interface but having them running in the GT2 "low power mode" rather than the GT4 "max performance mode".  The XPS 13 models prior to the current 9370 work this way, and running 4 lanes in GT2 mode gives basically the same performance as running 2 lanes in GT4 mode, in fact I personally have an XPS 13 9350 with a 960 Evo and I get basically those exact benchmark results.  This potential cause technically could be modified in firmware, but since Dell sold XPS 13s configured this way over a period of a few years and never added it as a configurable BIOS option, if that is the issue on your system, I would not expect them to change it there either.  As for why they designed it that way, I have some theories, but they would only be theories, and even if one of them happened to be correct, it wouldn't change the situation.

The bottom line is that unless you see options in your BIOS for how to run the NVMe interface, i.e. low power or max performance, then it's very likely that the performance you have now will be the best you will ever get on that particular system.  If you still want to know how many PCIe lanes are wired to your NVMe interface though, you could install the Samsung Magician software, which will tell you.  The catch though is that your system's SATA Operation would have to be in AHCI mode.  If it's in RAID mode, then Samsung Magician won't be able to show this information, and you can't just change from RAID to AHCI on an existing Windows installation.  Typically that's something you do before installing Windows at all.

Thanks "jphughan" for your prompt reply!

1) In BIOS version 1.14 there are no options for the NVMe interface (yet ;-)

2) Samsung Magician gives the following information:
- Interface: PCIe Gen. 3x4
- NVMe Drivers: Samsung
- TRIM Status: Enabled
- RAPID Mode: Not supported

3) HWiNFO64 gives the following information:

Device Name: Intel Skylake-U/Y PCH - PCI Express Root Port #9 [A1/C1]
PCI Express x1 Bus #4

General information

- Device Name: Samsung Electronics SSD 960 NVMe PCIe SSD Controller
- Device Class: NVMe Controller
- PCI Address Number: 4:0:0

PCI Express

Version: 3.0
Max Link

So it looks like 4 lanes are used together with PCIe 3.0, but still 1.800 Mb/s is the maximum....
All suggestions are welcome!

have you solved?

i have the same problem

only 1800 MB/s instead of 3400 MB/s (on reading)

writing speed is right (1500 MB/s)

my ssd is 970 EVO Samsung 256 GB

thanks

I have Inspiron 5570 (i7 8th gen). Recently I installed Samsung 970 Evo 250 GB. I am also facing the same issue.

I have changed BIOS from Raid to AHCI then installed fresh Windows. 

Now Windows boot time 14 Secs, MS Word, Excel are opening within 2 secs, Adobe PS CC is opening in 3 sec. But Samsung magician is showing Squential read speed 1812, Write 1542 .

Inspiron 5570 physically  has PCIe Gen 3 X 4 NVME Interface, and the CPU (Core i7-8550U) who supports GT4 which is technically required for Samsung 970 Evo's optimum performance. 

https://ark.intel.com/products/122589/Intel-Core-i7-8550U-Processor-8M-Cache-up-to-4_00-GHz

Then what is the problem with Dell 5570 ? 

Hi,
the same for Inspiron 5370 with core i7, the EVO 970 has 1800 MB/s read instead of 3200.
There is nowhere said that nvme interface is limited. I'm assuming it should run with PCIe 3x4 speed.
I've bought fast disk to get full speed of it and paid a lot for that.
Why dell is not showing this limitation in specification?

As a data point, I just installed the Samsung 1 Tb 960 EVO M.2 on my 5570 in RAID mode, and Samsung Magician is reporting:

• the disk is not supported (presumably because it's in RAID and not AHCI mode?)
• 1830 Read, 1696 Write Mb/s
• 83,496 Read, 72,021 IOPS

I'm pretty happy with the performance and the sub 30 second boot time, but yes, if it could be doubled, well come on Dell, let's do it!

I'm in the same boat. I bought an Inspiron 15 / 7000 (Model 7572)  in May. I removed the 128gb M2 SATA ( which they said in writing was NVME and then denied) bought the 970 evo 500gb and its on 1800 mb/s not around the 3000 I was expecting

So funny status of this thread is - SOLVED ?????

I believe this is final nail in the coffin :

Dell inspiron 5570 with i7-8550U and external graphics.

CPU lanes (from https://ark.intel.com/products/122589/Intel-Core-i7-8550U-Processor-8M-Cache-up-to-4-00-GHz-)

ARE : 1x4, 2x2, 1x2+2x1 and 4x1

If 4x lane is connected TO GRAPHICS CARD.

HOW it could be also 4x lane connected to NVMe SLOT ?