Are All M.2 SSD's Fast?

[Ali_Baba]

My friends and I got into an argument the other day. One of my friends, Felipe, is making a pc (Ryzen 7, GTX 1080ti, the works) and he opted to buy an M.2 SATA SSD over a conventional SSD (this one: http://). Both my friends Darius and Felipe are under the impression that an M.2 drive will always outperform a conventional SATA SSD. I tried to explain to them that just because the drive is connected to the M.2 interface, it doesn't mean that they will be achieving 32Gb/s, just as a drive connected to the SATA interface doesn't mean that it will achieve 6Gb/s. I went on to say that the drive that Felipe is buying will not outperform a conventional SSD because the drive that he is buying is an M.2 SATA SSD. I went on to show them how the specs of the Samsung 850 Evo 250GB 2.5" SSD and the Samsung 850 Evo M.2 SATA SSD were exactly the same.I tried to explain that the only way that they were going to achieve better performance is by buying an NVMe or PCIe M.2 SSD. Then my friend pointed out that a SATA drive uses dedicated cables and the M.2 drives are plugged right into the board, making the M.2 drive faster by default. My point is, is there anyone out there that knows more about SSD's than we do and try to explain which one of us is right.

 

[photonboy]

There is no appreciable difference in performance between some SATA SSD's and some M.2 SSD's. I'll try to find a link.

Rather than find the link that I know will confirm older M.2 SSD's were the same performance, here's an article that talks about how the NEWER M.2 SSD's are faster even if the memory has similar read/write characteristics:
http://www.computershopper.com/feature/2017-guide-the-best-m.2-solid-state-drives-tested

"Until a year or so ago, most of these M.2 PCI Express SSDs made use of the PCI Express Gen 2.0 x2 interface, which defines a throughput ceiling that's higher than SATA 3.0's, but not enormously so. That's changed. Most new, high-end M.2 drives, nowadays, support next-generation PCI Express x4 paired with a technology called NVMe (Non-Volatile Memory Express) to propel performance even further, especially with heavy, deeply queued workloads."

(not sure about that "but not enormously so" because I've seen benchmarks that showed the EXACT same performance so there must have still been a bottleneck elsewhere... POTENTIAL and actual performance are different things)

*So you are BOTH right from a certain point of view (older M.2 versus newer M.2). Having said that there are probably still M.2 SSD's that are roughly the same speed. Again, there are different areas that can bottleneck performance such as the CACHE used, and when you populate the cache the performance of the main memory is critical so a PRO SAMSUNG SATA would probably still beat a lower-end M.2 SSD in certain scenarios.

 

[rgd1101]

There are pcie interface or sata interface for m.2 form
with sata interface, it the same as the 2.5" form

 

[photonboy]

Other:
Just FYI, but unless you're doing something intensive like video editing it's nearly IMPOSSIBLE to notice a real-world difference between any SSD (I'm sure some people will disagree). I had to swap out my faster SAMSUNG 850 PRO for an older Vertex 2 which was much slower and my PC felt about the same.

Part of the reason for this is that programs and other data end up in the main system memory (DDR3,DDR4) and get read from there much of the time. For example, if I started a program it might launch from SSD the first time, but then from my DDR3 memory the second time (and stay there until a reboot or if I run out of memory and Windows flushes some data from main memory).