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SATA3 to PCIe upgrade (M.2 2x2/adapter 3x4)


I have an opportunity to “sell” my Samsung 840 pro for ~50 €.
My MSI Z97G7 should be equipped with PCIe Gen2 x2 M2 slot. Is it worth to upgrade to nvme? My candidates are XPG SX8200 Pro or Samsung 970 Evo Plus in 250GB size.

From what I’ve read and watched, it would definitely be worth it for large files transfer, e.g. video editing.
In my system I use ssd for operating system (w10) + programs solely, mainly browsing, spreadsheets and occasional gaming + video edit (temp folder is on hdd).

Is it worth to upgrade 840pro sata3 for NVMe in PCIe Gen2x2?
Am I going to notice any difference in my daily use? Boot times, program load times…
If not, are there any downsides of XPG SX8200 comparing to 840pro? Longetivity? I’ve heard, temperature might be an issue with nvme flash.

Also, I believe the “sell” deserves a little explanation: I’m in process of buying an ssd for ~10 yo laptop. 500GB samsung evo has been chosen. I’ve offered my unused 840 evo from a laptop, since that 10yo family notebook won’t notice a difference between new and old ssd (cpu and ram are likely to be bottleneck here - Core2Duo w 4gb ram). I’ll move my 840pro from main rig to my mostly unused laptop, and thus the “sell/swap” opportunity.

Most likely not.

The drive will be bottlenecked to ~900MB/s anyhow by the 2 lane slot.

That will slow down any good NVMe drive. With that speed you can go much much cheaper with something like ADATA SX6000.

Maybe, maybe not. I have upgraded a sata3 to NVMe, but my NVMe is x4, so it’s full speed. I have noticed a difference, but X2 you may not… On paper it’s faster, but I’m not sure it’s worth it.

Here’s the thing. If you are gonna upgrade your entire system soon then OK, go for the NVMe. The new system will take advantage of it’s full potential. Buying 3,5GB read NVMe to use it on Z97 with x2 slot is not worth it. Get an XPG XS6000 instead. Cheaper and is made for X2 slots, so the board and the drive won’t cripple each other.

If I understood it correctly, once the board supports NVMe booting (from M.2), it should support it from PCI adapter as well.
So theoretically, I could place it in PCIe -> M.2 adapter (another 10-20€) and connect directly to motherboard, skipping the M.2 on my motherboard.

Question remains, if it’s worth it. I’m going to spend the money anyway - either for 2,5inch drive for old laptop, or NVMe for my rig…


Guys, I did more research on the topic, but I still have a couple questions, I would like you to help me with.

I understand, that my M.2 connector is PCIe2x2, whereas top NVMe drives is capable of PCIe3x4. We are talking about 10Gbit vs 40Gbit max theoretical speed.
If we have a look at 970 EVO Plus 500G benchmark and its average read speed of 2387MBps, I would definitely be limited by my m.2 port.
On the other hand, if we look at 4K read, we are at 63,6MBps. This is well below max bandwidth of 2x2.

Question is, if I can reach the 63,6MB on PCIe2x2 (since 63,6MB < 10Gb), or it doesn’t work like that?

Manual for my motherboard doesn’t explicitly state it, but I expect the M.2 PCIe is connected to Z97 chipset instead of CPU

When I decided to go for PCIe -> M.2 adapter (let’s forget about onboard M.2 for a moment), I should be able to run full speed, since my board has 3 PCI-EX16 ports in Gen3 (16,0,0), (8,8,0), (8,4,4) configuration and 4 PCI-EX1 ports.

I currently have GTX780 plugged in topmost PCI-EX16 plugged in and Asus wificard in PCI-EX1.

If I understand it right, plugging PCIe -> M.2 adapter into another PCI-EX16 slot is going to “steal” 8 lanes, leaving 8 for the GPU, correct?
Is there any way to try how would my gpu perform on 8 lanes, without actually plugging something else in?

A bonus question (please express your opinion): I’m going to repurpose one of my current SSDs - 840pro 256G or 840evo 500G for old family laptop. Which of above would you keep and which let go.

IMHO if you really want to spend and don’t do lots of data transfers, stick with ordinary SATA. Its plenty fast, for gaming or office work NVMe has absolutely no advantage over SATA because speed difference is in the region of statistical error.

NVMe would be a logical choice if you recording 4K+ video on regular basis, rendering with vast shaders libraries or work with audio libraries in vast quantities or anything else data intensive like VM or databases.

Yes that’s how should be in theory with lane switching if you want to proceed with NVMe in second slot. From specs M.2 on-board really are not much faster than SATA. At least according to specs bottom slot is not wired to the chipset so yeah it should work 8/4/4. * But VGAs plugged into x8 slot sometimes do weird stuff and I can testify to that *

840 pro sould outlive SX8200 purely based on NAND used. MLC vs TLC. SX8200 SLC cache is tiny and not designed for permanent data storage area but as a cache. If you really worried about longevity then either buy solid MLC SATA drive (very few left on the market 99% are TLCs…hmm probably only Samsung Pros) or get 960 or 970 Pro Samsung NVMe. From all signs 970 Pro will be the last MLC based NVMe drive for consumer market. Manufacturers moving away from it to cheaper and worse or much much worse NAND - in order: TLC, QLC and now PLC on the horizon.