M2 benefit discussion

[Britgeezer]

Discussion point for Z/H97 chipset.



So is it true?

Most of my PC's only use an SSD - all file storage heavy lifting is done by my server.

Is there really a big benefit to use an M.2 with an SSD and if so is the OS installed on the M.2 or the SSD?

I can see M.2 with a spinning HD, but with an SSD? Convince me real world.

[parsec]

Re: M2 benefit discussion

First, M.2 is a form factor and an interface of a SSD. M.2 drives are SSDs, they are NAND flash storage devices.

Your Z97 Extreme6 board has two M.2 interfaces, the standard M.2 using two PCIe 2.0 lanes, and the Ultra M.2 (Ultra being ASRock's name, not an industry standard) which uses four PCIe 3.0 lanes. Both the PCIe and SATA III type M.2 SSDs connect to these "slots" or "ports".

Your comment about seeing "... M.2 with a spinning HD..." makes no sense to me, sorry to say.

Currently there are two types of M.2 SSDs, pure PCIe (my terminology) and standard SATA III. Each type uses a different SSD controller, and their data level interface to the rest of the PC is different.

The SATA III type uses a board's standard chipset SATA controller. They are not faster than standard 2.5" SATA III SSDs, but are equal to them in speed. Very few exist and offer nothing better than a standard SSD provides, except size and their one connection, no cables interface.

The PCIe type have their own built in equivalent of a SATA controller, which may use the same AHCI driver provided with an OS. They are faster than SATA III SSDs, but how much faster depends on several factors of their design and components.

The pure PCIe M.2 SSDs are more complex than standard SATA III SSDs, in that the SSD controller they use will have different IO interfaces of their own, that can differ from the external interface they connect to.

For example, the Plextor M6e, which is sold mounted to a PCIe slot adapter card, is really an M.2 interface SSD. It's output interface is on two PCIe 2.0 speed lanes.

The Samsung XP941, an M.2 interface SSD, has an output interface of four PCIe 2.0 lanes. Potential buyers must know what M.2 interface their board has, and what M.2 interface the M.2 drive they are considering has. Connecting an XP941 (PCIe 2.0 x4) to a standard M.2 interface (PCIe 2.0 x2) will result in a loss of performance.

There are very few M.2 drives currently available, the Plextor M6e and Samsung XP941 are the most well known.

Could you elaborate on what you are referring to about M.2 with HDDs, or are you thinking about something else?

[Britgeezer]

Re: M2 benefit discussion

Discussion point for Z/H97 chipset.

I can see M.2 with a spinning HD, but with an SSD? Convince me real world.

For clarity, many people are still using conventional HD (spinners) because of the lower cost per TB vs. SSD.

My question was for people already using SSD for OS and applications and most data stored on a dedicated Server (i.e. me) Is there really any real world benefit to use an M.2 with an SSD and if so is the OS installed on the M.2 or the SSD?

As you know the Z97Extreme4 has a dedicated M.2 slot so I was just trying to understand if the claimed bandwidth would add a performance boost to SSD worthwhile the cost.

[wtd03]

Re: M2 benefit discussion

Speaking of benefit is it really the case that you cannot do SLI two way with the samsung m2 installed?

Is my only multi card option really crossfire?

[parsec]

Re: M2 benefit discussion

For clarity, many people are still using conventional HD (spinners) because of the lower cost per TB vs. SSD.

My question was for people already using SSD for OS and applications and most data stored on a dedicated Server (i.e. me) Is there really any real world benefit to use an M.2 with an SSD and if so is the OS installed on the M.2 or the SSD?

As you know the Z97Extreme4 has a dedicated M.2 slot so I was just trying to understand if the claimed bandwidth would add a performance boost to SSD worthwhile the cost.

Sorry, I get it now, your terminology and my OCD about terminology caused my misunderstanding.

What would you consider a real world demonstration of any benefit?

IMO, given the current state of M.2 SSDs, compared to standard SATA III SSDs, there is very little benefit in using M.2 drives.

Yes they have higher sequential, large file read and write speeds. But the small file, 4K read and write speeds are no better than the best SATA III SSDs, and a few SATA III SSDs are a bit faster. As always, benefits depend upon what a user commonly does with their PC. If you are reading and writing many large files, the added large file read and write speeds will save you some time, depending upon the size of the files. But even with multi-gigabyte sized files, we are talking a few seconds difference. Create a RAID 0 array of two SATA III SSDs, and that difference disappears.

Most PC users never use the potential IO performance of standard SATA III SSDs, so the added high queue depth speed and IOP rates of M.2 SSDs will never be used.

There are other aspects of SSD performance, like consistently low IO latency (as shown in TweakTown SSD reviews), where some M.2 SSDs are inferior to the best SATA III SSDs, and significantly so.

So will an M.2 SSD be immediately noticeable faster than a standard high performance SATA III SSD, or long term? No, and certainly not for booting and running an OS.

I used a Plextor M6e for a while, and it worked fine and is fast, but it was not noticeably faster than my SanDisk Extreme II or Samsung 840 Pro SSDs.

The M.2 SSD market remains tiny, this review of the Samsung XP914 includes all the PCIe M.2 SSDs available (two models), and the others shown for comparison are not M.2 SSDs:

Samsung XP941 256GB Ultra M.2 PCIe SSD Review

As the review states at the end, we may see better PCIe M.2 SSD performance in upcoming products, but will the difference you asked about be there? We'll see.

[parsec]

Re: M2 benefit discussion

Speaking of benefit is it really the case that you cannot do SLI two way with the samsung m2 installed?

Is my only multi card option really crossfire?

Depends on the system you have, and basically the number of PCIe 3.0 lanes available.

"Mainstream" Intel CPUs provide 16 PCIe 3.0 or 2.0 lanes. In two way SLI, that is already x8 and x8.

Add an XP941 in the ASRock Ultra M.2 slot, using four PCIe 3.0 lanes, and you are left with 12 PCIe 3.0 lanes. So at best you have x8 and x4.

"High End Desk Top" Intel processors have up to 40 PCIe 3.0 lanes, so a mere four lanes for an Ultra M.2 slot is not a problem.

AMD boards and processors are not my thing.

[wtd03]

Re: M2 benefit discussion

Depends on the system you have, and basically the number of PCIe 3.0 lanes available.

"Mainstream" Intel CPUs provide 16 PCIe 3.0 or 2.0 lanes. In two way SLI, that is already x8 and x8.

Add an XP941 in the ASRock Ultra M.2 slot, using four PCIe 3.0 lanes, and you are left with 12 PCIe 3.0 lanes. So at best you have x8 and x4.

"High End Desk Top" Intel processors have up to 40 PCIe 3.0 lanes, so a mere four lanes for an Ultra M.2 slot is not a problem.

AMD boards and processors are not my thing.

When you say high end Intel Im assuming the 4960k/4790k correct?

Anyways I may just take this board back based on what you said in the other post about speeds being negligible on current SSD's. m.2 does sound good on paper but real life performance may not even matter. I bought this board on saturday because it had that ultra m.2 slot and that peaked my interest.

I may go towards an Asus or Gigabyte board now.

[Britgeezer]

Re: M2 benefit discussion

As the review states at the end, we may see better PCIe M.2 SSD performance in upcoming products, but will the difference you asked about be there? We'll see.

OK, so as I thought, maybe it can be seen on some benchmarks, but otherwise no need to speculate coin on M.2. if I'm already using an SSD.

[parsec]

Re: M2 benefit discussion

When you say high end Intel Im assuming the 4960k/4790k correct?

Anyways I may just take this board back based on what you said in the other post about speeds being negligible on current SSD's. m.2 does sound good on paper but real life performance may not even matter. I bought this board on saturday because it had that ultra m.2 slot and that peaked my interest.

I may go towards an Asus or Gigabyte board now.

Nope, 4960k/4790k are Mainstream processors with 16 PCIe 3.0 lanes.

HEDT processors are socket 2011 and 2011 v3 processors, that all have 40 PCIe lanes, except for the i7-5820K.

IMO, boards like this have more potential to be "future proof", due to their multiple IO interfaces. The gamble is which format becomes successful, M.2, SATA Express, whatever. But if a board has none of these interfaces, it has no chance of being future proof.