Ultra M.2 interface

[Flokiam]

Recently I been seeing the latest interface M.2 go yet again to another level, with speeds up to 32Gbs! Im wondering how they do it, and if you really could take advantage of such data transfers which looks pretty promising on paper..

[xLegendary]

Re: Ultra M.2 interface

[ocer9999]

Re: Ultra M.2 interface

Sounds cool, but is it possible to run some numbers on this?

[parsec]

Re: Ultra M.2 interface

The Ultra interface is there, but the M.2 SSD must match the interface or the result is barely different.

The M.2 SSD's controller is the key, whether or not it is an x4 interface (Samsung XP941 is the only one with that so far) and if the controller will work at PCIe 3.0 speeds (none of them do so far.)

The amount of "leftover" PCIe 3.0 lanes depends on the system, mainstream Intel CPUs have 16 PCIe 3.0 lanes, so one graphics card will be down to x8 if an x4 M.2 SSD is used.

The X99 platform provides more PCIe 3.0 lanes (28 - 40) so has more to share.

[tha original tunejunky]

Re: Ultra M.2 interface

unfortunately the vast majority of M.2 cards have the sata 3 controller so you're limited to 6gbs. i use the excellent plextor m6e m.2 which has a custom pcie controller and i use an asus (x99a) board with a purported x4 interface. i haven't benchmarked the speed but i'm well beyond any sata bottlenecking.
ALSO (!!!!) many boards with m.2 onboard *do not* offer pcie interfaces (most are z97) or when they do they limit it to the almost useless 2242 (42mm) size - i'm looking at you evga micro x99...
what i can say at least on the asus and with the plextor drives that the bandwidth/speed is so fast that it will take several generations of tech to catch up and bottleneck them.

[parsec]

Re: Ultra M.2 interface

The Plextor M6e has a PCIe 2.0 x2 Marvell controller, so cannot leverage the Ultra M.2 interface. I tested the 256GB version when they were first released:



The large file sequential speeds are beyond the standard SATA III limits of ~550MB/s read and ~530MB/s write, but the 4K random read speed is ~10% - 20% below the best SATA III SSDs, and the 4k write speed is also below those same SSDs.

[tha original tunejunky]

Re: Ultra M.2 interface

The Plextor M6e has a PCIe 2.0 x2 Marvell controller, so cannot leverage the Ultra M.2 interface. I tested the 256GB version when they were first released:

[ATTACH]7425[/ATTACH]

The large file sequential speeds are beyond the standard SATA III limits of ~550MB/s read and ~530MB/s write, but the 4K random read speed is ~10% - 20% below the best SATA III SSDs, and the 4k write speed is also below those same SSDs.

thanks for the benchmark. i have the samsung m.2 (pcie x4) on my xmas list so i'll compare the two. haven't noticed any speed drop off in random reads but you have the numbers right there. right now i use m.2 for boot only and the plextor is fantastic for that. i do have 2 m.2 slots so i'll try the samsung as a boot/game drive and look for appreciable differences.

[parsec]

Re: Ultra M.2 interface

I'm not saying that the M6e is really slower than other SSDs in its 4K read speed, any result in the mid 30's and above in AS SSD is among the best there is. A few regular SATA SSDs can give 36 - 40MB/s 4K read speeds in AS SSD, so the M.2 interface does not guarantee a SSD will surpass standard SATA SSDs in all areas of performance. It depends on how the firmware is tuned, and other factors.

The M6e was tuned for great high queue depth results, which we can see in the IOPs results of the same benchmark:



The 4K-64Thrd (high queue depth) results show over 100K IOPS for both read and write, which SATA III SSDs can't match. But PC users never have a situation where they will have 64 IO requests waiting to be processed, even when booting an OS. So while those numbers are impressive, the capability to work at that speed will never be used.