Did I pick the right SSD interface?

[Craig234]

I bought the Samsung 850 EVO 500GB drive yesterday.

I was a bit surprised at checkout to have a choice of like 'Sata III or M.2 or mSata' interfaces, and don't really have any idea what they are (just seen the terms).

I went with the default Sata III. Was that the right pick? The question might be 'what motherboard are you using', but don't have that yet, something to go with a 4790K.

 

[ShintaiDK]

mSATA and M.2 is a slot on the motherboard (If your mobo got any).

SATA is a cable connected like all HDs.

 

[mikeymikec]

SATA / SATA 6Gbps / SATA III is the most compatible choice you could have gone for, I would have done the same. IMO M.2's days are numbered unless it undergoes a physical revision.

 

[Craig234]

Thanks, good to hear it's the correct pick.

 

[Topweasel]

SATA / SATA 6Gbps / SATA III is the most compatible choice you could have gone for, I would have done the same. IMO M.2's days are numbered unless it undergoes a physical revision.

M.2's days are not numbered. Our problem is that it was developed specifically for OEM use and not aftermarket products.

Dell calls Samsung and asks for size options on a 850 pro equivalent 2248. Samsung tells them 256GB or 512GB. Dell submits a huge order for both. Our problem is that ASrock, Gigabyte, MSI, and Asus all offer different configurations of M.2 and our preferred SSD company might not have an available aftermarket solution for that size.

Sata-Express is our M.2 solution. That one though is struggling massively in getting any drive support.

 

[Insert_Nickname]

Sata-Express is our M.2 solution. That one though is struggling massively in getting any drive support.

I doubt that. To date, there have been zero drives available for SATA-Express. Besides, its limited to 2 lanes of PCIe 2.0 (3.0 as of Skylake). Almost all the new PCIe SSD controllers announced use 4 lanes of PCIe 3.0.

U.2 (SFF-8639), on the other hand, seems to be gaining a bit of traction in the enthusiast market.

 

[Craig234]

I was just browsing motherboards, and saw M.2 SSD support listed as 'up to 5 times the performance of Sata III'. That makes me wonder about Sata III?

Is it a case of for some reason you can't actually see the benefit, or is there more to the advantage of m.2?

 

[StrangerGuy]

I was just browsing motherboards, and saw M.2 SSD support listed as 'up to 5 times the performance of Sata III'. That makes me wonder about Sata III?

Is it a case of for some reason you can't actually see the benefit, or is there more to the advantage of m.2?

Anything beyond SATAIII is overrated as hell, especially by NVMe fanboys frothing their mouths over synthetic benchmark numbers. You are never going to see any real world improvement with those drives over a bog standard Samsung Evo 850 SATAIII in typical desktop / gaming workloads.

 

[Insert_Nickname]

Anything beyond SATAIII is overrated as hell, especially by NVMe fanboys frothing their mouths over synthetic benchmark numbers. You are never going to see any real world improvement with those drives over a bog standard Samsung Evo 850 SATAIII in typical desktop / gaming workloads.

That is a truth with a few modifications. You are going to notice quicker program startup with a PCIe drive, but this only applies to heavyweight applications. Also opening very large projects/files is quicker. But in ordinary day-to-day usage you're not going to notice much difference.

Whether or not that difference is worth the premium for a PCIe drive is a personal matter. For ordinary usage I'd agree the answer is no.

 

[mikeymikec]

"Never" is an awfully strong word to use in the future tense, especially when applied to technology.

---

AFAIK, SATA-Express and M.2 are horrid solutions for multiple storage devices demanding >6Gbps bandwidth, both for the same reason: Physical space used on the mainboard. The only workaround I can think of for M.2 would be a PCIE card to mount the M.2 cards on, and having multiple levels of cards, like how RAM slots in laptops are sometimes overlapping each other. That potentially results in one fat PCIE card though.

SATA-Express gets a bonus reason for the enormity of the connector required - I don't think anyone wants to revisit the days of attempting to route ribbon-style cabling through a computer chassis.

Are these stopgap solutions because no-one could come up with a better connector in time for... something?

 

[CakeMonster]

For the lazy.. what's the U.2 advantages compared to M.2?

 

[Topweasel]

I doubt that. To date, there have been zero drives available for SATA-Express. Besides, its limited to 2 lanes of PCIe 2.0 (3.0 as of Skylake). Almost all the new PCIe SSD controllers announced use 4 lanes of PCIe 3.0.

U.2 (SFF-8639), on the other hand, seems to be gaining a bit of traction in the enthusiast market.

Okay quick question. What is the intended market for NVMe connectors? Another question. What is the market for SATA-Express? Okay final question at what point do you expect to be able to purchase a Dell Desktop and have it support M.2 out of the box? Sorry one more... What is the ratio of SATA-Express support to M.2 support on retail motherboards?

NVMe was a standard developed for Laptop/Tablet/Ultrabook developers to agree on one standard connector for SSD's that would be faster than SATA-3 and be flexible to work in several form factors and situations. What it wasn't developed for was to be a desktop computer solution to remove the use of 2.5 drives in desktops. It's why until today there is not a retail M.2 drive solution. Why sell a retail version of a drive that only works in .1% of new computers built this year, let alone the .000001% currently in use systems that supports it.

I can't answer why SATA-express hasn't had any traction. If anything it's probably just waiting till the next release cycle because they weren't ready to have two different 2.5 controller and connector solutions. But if you PCI-Express to succeed on the desktop. You want to see SATA-Express get more adopted. Without express based SSD's will be limited to Mini-ITX mobo's and a few uber niche solutions (like Asrock).

 

[Insert_Nickname]

Okay quick question. What is the intended market for NVMe connectors? Another question. What is the market for SATA-Express? Okay final question at what point do you expect to be able to purchase a Dell Desktop and have it support M.2 out of the box? Sorry one more... What is the ratio of SATA-Express support to M.2 support on retail motherboards?

Doesn't matter if there are no SATAExpress (I'll just refer to it as SATAE to save typing) drives available. You can buy M.2 drives, and both SATA and PCIe ones at that.

Whether M.2 takes off in common pre-builts is a valid question, its actually being actively used in higher-end workstations. We'll likely just have to wait and see what happens.

NVMe was a standard developed for Laptop/Tablet/Ultrabook developers to agree on one standard connector for SSD's that would be faster than SATA-3 and be flexible to work in several form factors and situations. What it wasn't developed for was to be a desktop computer solution to remove the use of 2.5 drives in desktops. It's why until today there is not a retail M.2 drive solution. Why sell a retail version of a drive that only works in .1% of new computers built this year, let alone the .000001% currently in use systems that supports it.

I think you're confusing a few things here. SATA and NVMe are drive interface protocols, it doesn't matter which physical interface that protocol is used over. An older example would be SCSI. The physical SCSI interface is long dead, but the protocol used is still very much in use (enterprise SAS). SATA itself is just plain old IDE running over a serial back-end interface, instead of the older parallel one.

M.2 is just the physical interface/connector used. Which protocol used over it doesn't matter. That's why you see both SATA and PCIe drives using the (almost) same connector (different keying). PCIe is just the bus linking the SATA/NVMe controller to the CPU. Nothing more, and nothing less.

As for availability, SATA M.2 drives have been available retail for ~2 years. You have also been able to buy PCIe based M.2 drives at retail for 2 years (Plextor M6e).

You're right about PCIe drive compatibility, but that's because the popular Samsung XP941 and SM951 weren't meant to be available at retail. They actually use the SATA command set, but lack bootable OROMs. Some mainboard OEMs chose to add boot support on their own hook and semi-officially. If your mainboard doesn't support those drives, you can buy a Kingston HyperX Predator. Which will boot on pretty much any mainboard with PCIe connector that can fit either it or the included PCIe-to-M.2 adaptor.

NVMe support is still a bit spotty, most H/Z97 and all new Skylake (LGA-1151) boards have it, but not anything older.

I can't answer why SATA-express hasn't had any traction. If anything it's probably just waiting till the next release cycle because they weren't ready to have two different 2.5 controller and connector solutions. But if you PCI-Express to succeed on the desktop. You want to see SATA-Express get more adopted. Without express based SSD's will be limited to Mini-ITX mobo's and a few uber niche solutions (like Asrock).

Perhaps because developing SATAE controllers took longer then expected. In the meantime, those who needed something faster-then-SATA3-can-handle, used the only thing available at that time. The Samsung XP941, which only came in M.2 flavor, because of its laptop origins.

The physical design of the SATAE connector doesn't help either. Only PCIe 2.0 x2 (which is barely faster then SATA3) and brings back unpleasant memories of ribbon cables... D:

 

[Topweasel]

Read my original post on this thread and the post I responded to. I think you are just circling around my comments because you think I meant something I clearly did not mean. I say this because nothing you have said is any different then what I said but built around some M.2 viability. M.2 is usable in a Desktop environment now. But it's not the long term Desktop PC interface and it's use in the desktop environment is a stop gap till Sata-Express matures. That is not conjecture. It is a fact.

That said lets spend a little more time on your post.

Doesn't matter if there are no SATAExpress (I'll just refer to it as SATAE to save typing) drives available. You can buy M.2 drives, and both SATA and PCIe ones at that.

Whether M.2 takes off in common pre-builts is a valid question, its actually being actively used in higher-end workstations. We'll likely just have to wait and see what happens.

Again nothing that I didn't already state. Higher end workstations workaround this specifically because its a really fast solution and Sata-Express has no available drives.

I think you're confusing a few things here. SATA and NVMe are drive interface protocols, it doesn't matter which physical interface that protocol is used over. An older example would be SCSI. The physical SCSI interface is long dead, but the protocol used is still very much in use (enterprise SAS). SATA itself is just plain old IDE running over a serial back-end interface, instead of the older parallel one.

M.2 is just the physical interface/connector used. Which protocol used over it doesn't matter. That's why you see both SATA and PCIe drives using the (almost) same connector (different keying). PCIe is just the bus linking the SATA/NVMe controller to the CPU. Nothing more, and nothing less.

Sorry I used NVMe in the wrong circumstance there. My mind mixed the process for creation of M.2. Either way just replace that reference and just stick with M.2.

As for availability, SATA M.2 drives have been available retail for ~2 years. You have also been able to buy PCIe based M.2 drives at retail for 2 years (Plextor M6e).

I wouldn't really call a Plextor retail product a real retail product. I get that it is. But it was always a Liteon OEM drive. Since Plextor's deal with Lite-on any version that they sell has to be Retail. But eventually I expect more retail "upgrade" options in the future. But really that market is for after purchase upgrades for laptops that use it. The bus links, Sata vs. PCI-E communication questions, and length limit the ability for these drives to become an actual retail cornerstones.

You're right about PCIe drive compatibility, but that's because the popular Samsung XP941 and SM951 weren't meant to be available at retail. They actually use the SATA command set, but lack bootable OROMs. Some mainboard OEMs chose to add boot support on their own hook and semi-officially. If your mainboard doesn't support those drives, you can buy a Kingston HyperX Predator. Which will boot on pretty much any mainboard with PCIe connector that can fit either it or the included PCIe-to-M.2 adaptor.

You can buy this not really retail adapter to get your not really retail drive to work on a system that doesn't really support it is another stumbling block. But that's the problem when your jumping the gun. But part of that was ultrabook guys wanted a smaller connector for 64/128gb SSDs than mSata and pushed out the format before a lot of it was settled completely. But this all goes back to the main point. M.2 is not targeted and will eventually go away on all but itx boards as adoption and implementation of a Desktop oriented PCI-e based communication system grows. That should be at this point Sata-express.

NVMe support is still a bit spotty, most H/Z97 and all new Skylake (LGA-1151) boards have it, but not anything older.



Perhaps because developing SATAE controllers took longer then expected. In the meantime, those who needed something faster-then-SATA3-can-handle, used the only thing available at that time. The Samsung XP941, which only came in M.2 flavor, because of its laptop origins.

Exactly my point. Just because people are using M.2 because its the only thing out there right now in their PC's doesn't make it viable. It isn't because the general user has to hop through to many hoops. Its not a desktop solution. I don't even know why this is a debate.

The physical design of the SATAE connector doesn't help either. Only PCIe 2.0 x2 (which is barely faster then SATA3) and brings back unpleasant memories of ribbon cables... D:

Well cabling aside PCIe x2 decision probably had more to do with 1. Not requiring to many of the PCIe lanes since intel is slow in adding them to the new CPU archs and otherwise would require licensing plx chips from nvidia. 2. Future upgrades by basically designing it already outdated. When they are ready implementing PCIe 3.0 will be a cakewalk and nearly double the potential performance. 3. By starting back farther they don't really have to worry about holding silicon back while waiting for the the next PCIe standard. So lets say 4.0 is coming out, if it gets delayed, they can still go forward with PCIe 3.0 in the mean time. Whereas if they start now on 3.0 if 4 is on the horizon. They either A.) ignore it for a generation or B.) Hold back stock till the standard is finalized and they have a fully developed controller.

But again the TLDR. Nothing in what you said goes against my original point that A.) M.2 isn't going anywhere and B.) It's not the desktop environment implementation of a faster HD connector and the one we need to survive and be viable is Sata-express. It being usable on the desktop isn't what makes it viable and unlike mSATA, M.2's design choices made by the OEM's specifically make it even more nonviable than mSATA.

 

[Insert_Nickname]

Read my original post on this thread and the post I responded to. I think you are just circling around my comments because you think I meant something I clearly did not mean. I say this because nothing you have said is any different then what I said but built around some M.2 viability. M.2 is usable in a Desktop environment now. But it's not the long term Desktop PC interface and it's use in the desktop environment is a stop gap till Sata-Express matures. That is not conjecture. It is a fact.

Who cares if its a mobile interface? If it works, it works. You are aware that outside the HEDT platforms, modern desktop PC have a lot more in common with laptops then you might think at first glance. "Desktop" isn't desktop any more, its mobile-on-desktop.

Besides, SATAE is already being superseded. See below.

Again nothing that I didn't already state. Higher end workstations workaround this specifically because its a really fast solution and Sata-Express has no available drives.

Or you can just use a "pure" PCIe drive like the Intel SSD 750.

I wouldn't really call a Plextor retail product a real retail product. I get that it is. But it was always a Liteon OEM drive. Since Plextor's deal with Lite-on any version that they sell has to be Retail.

Retail = available to buy in stores. Who the OEM is doesn't matter.

Am I missing something here?

You can buy this not really retail adapter to get your not really retail drive to work on a system that doesn't really support it is another stumbling block. But that's the problem when your jumping the gun. But part of that was ultrabook guys wanted a smaller connector for 64/128gb SSDs than mSata and pushed out the format before a lot of it was settled completely. But this all goes back to the main point. M.2 is not targeted and will eventually go away on all but itx boards as adoption and implementation of a Desktop oriented PCI-e based communication system grows. That should be at this point Sata-express.

Exactly my point. Just because people are using M.2 because its the only thing out there right now in their PC's doesn't make it viable. It isn't because the general user has to hop through to many hoops. Its not a desktop solution. I don't even know why this is a debate.

It isn't the only thing. Again, "pure" PCIe drives are available. If a bit expensive.

Also, the M.2 socket isn't just used for SSDs. Its used for WIFI/Bluetooth cards, and such, too.

Well cabling aside PCIe x2 decision probably had more to do with 1. Not requiring to many of the PCIe lanes since intel is slow in adding them to the new CPU archs and otherwise would require licensing plx chips from nvidia. 2. Future upgrades by basically designing it already outdated. When they are ready implementing PCIe 3.0 will be a cakewalk and nearly double the potential performance. 3. By starting back farther they don't really have to worry about holding silicon back while waiting for the the next PCIe standard. So lets say 4.0 is coming out, if it gets delayed, they can still go forward with PCIe 3.0 in the mean time. Whereas if they start now on 3.0 if 4 is on the horizon. They either A.) ignore it for a generation or B.) Hold back stock till the standard is finalized and they have a fully developed controller.

But again the TLDR. Nothing in what you said goes against my original point that A.) M.2 isn't going anywhere and B.) It's not the desktop environment implementation of a faster HD connector and the one we need to survive and be viable is Sata-express. It being usable on the desktop isn't what makes it viable and unlike mSATA, M.2's design choices made by the OEM's specifically make it even more nonviable than mSATA.

A) Samsung seems to disagree with you, having just made the retail version of the SM951 NVMe available branded as the 950PRO.

Personally I actually think moving desktop drives to M.2 makes good sense, since eliminating the cables reduces cable clutter, and that makes for smoother airflow inside the case.

Since most mid to high-end Skylake boards have (on occasion 2) M.2 slots, its not going anywhere.

B) We already have the successor for SATAE. Its called U.2 (renamed/rebranded SFF-8639 connector). Cabled PCIe 3.0 x4 using an already industry standard commodity plug. I don't see any reason to bother with SATAE going forward, unless one needs backward compatibility for ordinary SATA. This goes double since no drives are available for SATAE anyway. There is therefore no reason to bother with backwards compatibility on that count.

 

[Craig234]

And I was reassured a second time. Then in today's Samsung 950 review:

"As a sign of where the SSD market is going, the 950 Pro clearly shows that SSD performance can be improved. Before too long, "high-end SATA SSD" will be an oxymoron; it's time for the transition to PCIe! "

 

[Asphodelus]

And I was reassured a second time. Then in today's Samsung 950 review:

"As a sign of where the SSD market is going, the 950 Pro clearly shows that SSD performance can be improved. Before too long, "high-end SATA SSD" will be an oxymoron; it's time for the transition to PCIe! "

There are at least 5 dimensions (more if you count all of the sub-dimensions) at play when choosing an SSD these days:

1. The physical connector/form factor: 2.5" SATA, mSATA, M.2, U.2, PCIe (in the sense of a board with gold pins on the long side and a metal bracket at the back, like your GPU), and theoretically SATA Express
2. The bus: SATA III vs PCIe
3. The data transfer protocol: AHCI vs NVMe
4. The controller and firmware
5. The NAND : MLC vs TLC, ONFi vs Toggle, planar vs 3D, process node, manufacturer

The first, second and third dimensions are directly interconnected and the fourth dimension is indirectly related as well, but even then there's tons and tons of possible combinations.

Now let's examine the 850 EVO that you're buying. First of all, let's get the easy part, the NAND (dimension 5) out of the way - all 3 variations have the exact same 3D TLC NAND, so there's no difference here.

Now for the hard part. The controller (dimension 4) was designed for SATA III (dimension 2) and AHCI (dimension 3), so it can never go any faster than ~500 MB/s regardless of which connector/form factor (dimension 1) you chose since this drive's bottleneck is dimension 2. In fact, I've heard that the M.2 and mSATA versions have overheating problems (which results in throttling, just like your CPU or GPU), so the SATA version might very well be the fastest of the 3.

If you want more performance than that, you're going to have to pay more for an SSD that's superior in one or more of the above dimensions.

Confused yet? :biggrin:

 

[oliver03]

Hey Craig234,

Not to add to the confusion, but just to wrap things up nice and easy,

I bought the Samsung 850 EVO 500GB drive yesterday.

I was a bit surprised at checkout to have a choice of like 'Sata III or M.2 or mSata' interfaces, and don't really have any idea what they are (just seen the terms).

I went with the default Sata III. Was that the right pick? The question might be 'what motherboard are you using', but don't have that yet, something to go with a 4790K.

You can not actually go wrong, "interfaces" are simply the physical connectors between your SSD and Samsung motherboard. All will work just fine.

Their brief descriptions, in regards to SSD

SATA SSDs
The latest, SATA III is up to 6Gbit/s (which translates to around ~550MB/s in the real world) and has the maximum compatibility across all motherboards and gaming notebooks. Only Ultrabooks with ultra-slim profiles cannot accommodate them.

mSATA SSDs
mSATA SSDs follow the SATA specification, offering the same maximum performance of 6Gbit/s and look much like mini-PCI-Express devices, but the two connectors are not inter-compatible. Note that mSATA is on it's way from being phased out and totally replaced with the better designed M.2.

M.2 Connector (NGFF)
M.2 is also known as NGFF (next generation form factor), and is the current connector standard for mobile SSDs, although it has also been adopted by motherboards as well. M.2 connector can plug in both PCI-Express-based and SATA-based SSDs, but is generally PCI-Express-based only, but again, with SATA is not inter-compatible.

4790K refers to Intel Core i7, your high end 4GHz, Quad Core processor, based on Intel's fourth generation Core architecture.

Don't worry too much about all our rather technical definitions.

Insert_Nickname stated it very well with regards to PCIe drive and heavy weight applications..

in ordinary day-to-day usage you're not going to notice much difference.

Whether or not that difference is worth the premium for a PCIe drive is a personal matter. For ordinary usage I'd agree the answer is no.)

and hey, congratulations on your new toy. :\

 

[tweakboy]

That is a great SSD will serve you for years to come. gl