Upgrade path for Dell gaming laptop; add an M.2 SSD, or RAM

I just picked up a Dell Inspiron 15 7000 Gaming laptop:
i5-7300HD quad core
1Tb 5400 RPM Hybrid HDD
8GB DDR4 2400MHz Ram

This laptop has a slot for an M.2 drive and I'm considering gettting one as the boot/progams drive and dedicate the HDD as storage.

The M.2 drives are pretty expensive still so I'd likely only be able to afford a 250Gb SATA-III ( not a PCI-e or NVMe). That said, do you think that's a sensible upgrade path? Even with the lower SATA transfer speeds compared to the others?
My other path was to get another 8Gb stick of ram for a total of 16GB.

I can do one or the other, not both right now.

This will be primarily a media center rig, and some video editing. I dont PC game much these days.

 

For some 120-130$ you can grab a 512GB MX300 m.2 SATA SSD, unless you are doing DB work, a SATA vs NVMe is a bit meh for the average user, its nice to see higher numbers on a bench program, but paying the same for half the storage is a bit dumb when you dont have unlimited budget.

A SATA SSD crushes any HDD, and its better to have more space at SATA SSD speeds than to have Windows and 2 programs on an NVMe and the rest on HDD's because the NVMe is already full. If you are doing video, depends a bit more, but I would prefer to have more video on SSD, because your i5 will limit encode speeds, so I dont think you would take FULL advantage of an NVMe SSD if it means that it will be smaller.

Check if the laptop has one or two sticks(either 1x8GB or 2x4GB), if it only has one stick, dual channel helps a bit on the performance, if its already dual channel(2x4GB), then you are going to need to buy 2 sticks to go up to 16GB or be happy with 8+4GB(dual channel still works up to 8GB(4+4GB) and the remaining 4GB are run at single channel.

 

Geat advice!
Kinda bummed. I got a little impatient and ordered a Samsung 960 EVO Series - 250GB PCIe NVMe - M.2 last night on Amazon.

That was before you posted your thoughts on a 512 MX300 SATA, and yes for $20 more I could've got twice the capacity.
See, I was under the impression that NVMe is to SATA as SATA is to HDD. So I really wanted to get the best speeds, but honestly if the speeds of SATA to NVMe yield diminishing returns for the work I'll be doing I may reverse my order.

This right here makes a lot of sense

I think I need to be more realistic with my needs.

 

2 seconds difference on boot, if that, comparing an NVMe to a SATA SSD, but a SATA SSD vs an HDD will be leaps and bounds better.

It is indeed diminishing returns, its an order of magnitude or more on access times on ssd vs hdd, but on sata ssd vs nvme, its just same order, but lower values, you can notice the difference, but only on limited use cases.

 

Thank you for the sound advice. I went ahead and cancelled my order for the EVO 960 and went with this option instead:
Crucial MX300 525GB 3D NAND SATA M.2

I'd be fooling myself if thought I needed much more than that for speeds.