Samsung 970 EVO plus is giving half the expected speed on hp notebook 15g - dr0006tx

[suvansh-rana]

Product Name: HP Notebook - 15g-dr0006tx
Operating System: Ubuntu 20.10

I recently added Samsung's 970 EVO Plus NVMe M.2 SSD (250GB) to my laptop. 
( https://www.samsung.com/in/memory-storage/nvme-ssd/970-evo-plus-nvme-m-2-ssd-250gb-mz-v7s250bw/ )

The expected speed of the SSD (given on Samsung's website) is: 3500MB/s{read] & 2200MB/s[write]

The speed that I'm actually getting on my laptop is:  1500MB/s[read] & 1600MB/s[write]

Screenshot of Read/Write test of my SSD:

The SSD's firmware is up-to-date and the SSD is working fine. But it is not giving the expected speed.

I have done some research and I think my SSD and Operating System are properly configured.

So my question is:
Is my laptop not designed to run on full speeds of a PCIe NVMe SSD?

The given thread is the reason I have this doubt:
https://h30434.www3.hp.com/t5/Notebook-Hardware-and-Upgrade-Questions/What-type-of-SSD-does-HP-Noteb...

Thread Title: What type of SSD does HP Notebook - 15g-dr0006tx support

As you can see above, The HP expert has mentioned that "it may not run on full PCIe speed". 

So does it mean that hp 15g - dr0006tx  cannot run on full speeds of a PCIe NVMe SSD due to hardware shortcomings?

PS: I have Ubuntu 20.10 installed but I'm not sure whether Ubuntu is the reason for slow speeds of the SSD or not. As far as I  have researched Ubuntu comes with inbuilt NVMe drivers.

[stevecomputer]

The speed can be limited by the pcie revision. The top quoted speed is depending on optimal conditions and latest pcie revisions. If your pcie slot is lower, rev2 or rev1 then it will be throttled by that.