Does more Gigabit Per Second matter on storage speed?

[Ferrariassassin]

I see the term "Gb/s" on so many storage devices but what does it mean? Does it have to do with how fast the storage communicates with the motherboard? I have seen for example a Samsung 850 EVO with 540 MB/s write and 520 MB/s but has 6Gb/s read which i understand but than i see something like an M.2. with the same Read and Write as the Samsung 850 EVO except the Gb/s on this is 32 Gb/s instead of 6 Gb/s like the Samsung 850 EVO. I thought that the only thinkg that determines how fast a storage device works is the Read and write so does Gb/s matter just as much, is there a noticeable difference between 32 Gb/s and 6 Gb/s?

 

[ajhockey3]

the GB/S is the max throughput on the connector used in that storage device Sata 3 is upto 6GB/s (Gigabits not gigabytes)
M.2 drives connect directly through the PCI E lanes for super fact connectivity. The only reason they enclude the 32gb/s and gb/s is to try to fool people.

 

[MarkW]

Yes.

For example, a new hard drive today generally can read at between 100MB/sec and 120MB/sec.
But a good SSD, like the Samsung 850 EVO can read at 550MB/sec. That is why we like SSD's so much.

Newer M.2 SSD's that can use 4x M.2 slots, will go up to about 1000MB/sec, and some bootable PCIe and NVMe SSD cards can go well beyond those numbers.

Next year, Intel will be releasing Optane cards with their new XPoint (crosspoint) memory, which will act as an SSD does, but at almost 10 times the performance of PCIe SSD cards today. Micron/Crucial makes that XPoint memory in their fabs, and will also be coming out with products using that XPoint memory.

Just to show what a SSD can do, this is my Samsung 840 EVO 1TB SSD last month.

 

[atheus]

Hmm... that response isn't quite on the mark. For starters, you have to pay attention to the "B" when you see Gbps or Gb/s. Upper case B means Bytes, while lower case b means bits. A Byte is 8 bits. The marketing isn't necessarily to fool you, either. The industry has been using both terms for various transfer types since the beginning, before marketing had anything to do with it. Sure, it would be simpler for consumers if everyone used one or the other, but oh well.

With any drive, you have two types of figures to think about. The first is the bandwidth limit of the connection to the motherboard, which as ajhockey pointed out (although somewhat incorrectly) is 6 Gb/s (bits, not bytes). That perplexingly translates to only 600 MB/s, which you probably noticed is not 1/8 of 6 Gbps, but 1/10. I'm not entirely certain why this is, but I suspect it has something to do with parity bits or overhead in the transfer protocol.

The second thing to think about is how fast the drive can actually read or write data, which is often not at the maximum rate the wire can sustain due to limitations of the drive hardware/firmware. Currently, most SATA SSD's transfer around 500+ MB/s, which is so close to the bandwidth limit of the SATA that it's often limited by the SATA protocol, which is why M.2 is so interesting. M.2 is 2-8x faster (depending on whether it's x1, x2 or x4), giving SSD's a lot more available bandwidth to potentially transfer data even faster. It then becomes a question of how fast the drive itself can read or write which determines performance, rather than what the data bus can handle.

 

[Ferrariassassin]

the GB/S is the max throughput on the connector used in that storage device Sata 3 is upto 6GB/s (Gigabits not gigabytes)
M.2 drives connect directly through the PCI E lanes for super fact connectivity. The only reason they enclude the 32gb/s and gb/s is to try to fool people.

Well can you tell a differene between 6 Gb/s and 32 Gb/s? And i think you mean Gb/s not GB/S because i think the second one means Gigabyte per second which would be fast as hell for an SSD or any storage device lol.

 

[MarkW]

Well can you tell a differene between 6 Gb/s and 32 Gb/s? And i think you mean Gb/s not GB/S because i think the second one means Gigabyte per second which would be fast as hell for an SSD or any storage device lol.

I listed that. M.2 x4 SSD should reach roughly 1000MB/sec.

 

[atheus]

Well can you tell a differene between 6 Gb/s and 32 Gb/s? And i think you mean Gb/s not GB/S because i think the second one means Gigabyte per second which would be fast as hell for an SSD or any storage device lol.

I listed that. M.2 x4 SSD should reach roughly 1000MB/sec.

M.2 is [strike]500[/strike] 1000 MB/s per lane, so M.2 x2 is [strike]1000 [/strike] 2000 MB/s, x4 is [strike]2000 [/strike] 4000MB/s.

 

[Ferrariassassin]

Yes.

For example, a new hard drive today generally can read at between 100MB/sec and 120MB/sec.
But a good SSD, like the Samsung 850 EVO can read at 550MB/sec. That is why we like SSD's so much.

Newer M.2 SSD's that can use 4x M.2 slots, will go up to about 1000MB/sec, and some bootable PCIe and NVMe SSD cards can go well beyond those numbers.

Next year, Intel will be releasing Optane cards with their new XPoint (crosspoint) memory, which will act as an SSD does, but at almost 10 times the performance of PCIe SSD cards today. Micron/Crucial makes that XPoint memory in their fabs, and will also be coming out with products using that XPoint memory.

Just to show what a SSD can do, this is my Samsung 840 EVO 1TB SSD last month.

Same one i got man cool I got the 250GB though and such. i am buying that new Intel 400GB 750400Gb PCIe one i heard its the fastes you can buy and i am so exited for it.

 

[Ferrariassassin]

Guys, you do realize that i am not talking about the read or write speed? I am not tlaking about that. i am talking about connection speeds in Gb/s.

 

[Ferrariassassin]

Hmm... that response isn't quite on the mark. For starters, you have to pay attention to the "B" when you see Gbps or Gb/s. Upper case B means Bytes, while lower case b means bits. A Byte is 8 bits. The marketing isn't necessarily to fool you, either. The industry has been using both terms for various transfer types since the beginning, before marketing had anything to do with it. Sure, it would be simpler for consumers if everyone used one or the other, but oh well.

With any drive, you have two types of figures to think about. The first is the bandwidth limit of the connection to the motherboard, which as ajhockey pointed out (although somewhat incorrectly) is 6 Gb/s (bits, not bytes). That perplexingly translates to only 600 MB/s, which you probably noticed is not 1/8 of 6 Gbps, but 1/10. I'm not entirely certain why this is, but I suspect it has something to do with parity bits or overhead in the transfer protocol.

The second thing to think about is how fast the drive can actually read or write data, which is often not at the maximum rate the wire can sustain due to limitations of the drive hardware/firmware. Currently, most SATA SSD's transfer around 500+ MB/s, which is so close to the bandwidth limit of the SATA that it's often limited by the SATA protocol, which is why M.2 is so interesting. M.2 is 2-4x faster (depending on whether it's x2 or x4), giving SSD's a lot more available bandwidth to potentially transfer data even faster. It then becomes a question of how fast the drive itself can read or write which determines performance, rather than what the data bus can handle.

So SATA is limited by 6 Gb/s right? Also what is the limit to M.2.? I heard it was 32 Gb/s is that correct?

 

[atheus]

So SATA is limited by 6 Gb/s right? Also what is the limit to M.2.? I heard it was 32 Gb/s is that correct?

M.2 is connected to your PCIE bus, and currently there are two options for M.2 slots. There's M.2 with 2 PCIE lanes, and M.2 with 4 PCIE lanes, which is often called "Ultra M.2". Z170 boards for the most part all have Ultra M.2 connections, while with Z97 boards Ultra M.2 is rare except on high end boards, though usually only the ones released later in the product cycle.

[strike]As I mentioned before, M.2 has 500 MB/s per lane, so an x2 slot is 1 GB/s or 8 Gb/s, while an x4 is 2 GB/s or 16 Gb/s. You would need 8 PCIE 3.0 lanes to make 32 Gb/s.[/strike]

M.2 has 1 GB/s per lane, so an x2 slot is 2 GB/s or 16 Gb/s, while an x4 is 4 GB/s or 32 Gb/s. Apologies for the incorrect info I posted previously!

 

[MarkW]

We ARE talking about throughput. That is what we see. It is what matters.

Now I was saying M.2 x4 SSD = 1000MB/sec. Its actually a bit higher than that. This is a screenshot of an M.2 x2 SSD being benchmarked. So for a x4 unit, you can pretty much double these numbers.

This image came from:
http://www.guru3d.com/articles-pages/msi-z97-xpower-ac-motherboard-review,18.html

So instead of 1000BM/sec, its closer to 1440MB/sec at x4.

 

[atheus]

Eh, to have a clear idea of what's going on one needs to have an understanding of both the performance limits of the protocol and the performance limits of the drive.

 

[MarkW]

To be real honest with you, I could care less what the protocol does or doesn't do. Its the results that matter.

I know that for engineers, those things are huge. Maybe even for programmers that have to work with the low level stuff. And I have been a programmer for most of my life.

But now that I can just be a user, those people can deal with the protocol stuff. I just want my data to move around so fast that I literally say, "Wow! Its done already??" and then I can smile!

 

[atheus]

You're trying to dumb it down too much. If all you care about is "results" and don't bother to try to understand the features and limits of the protocol, you may foolishly buy a Samsung SM951 and plug it into an M.2 x2 slot, then wonder why it's not benching as well as other people with the same drive. Sure, it will work in an x2 slot, but it will be choked for bandwidth until you put it into an x4 slot.

Furthermore, without at least a rudimentary understanding the protocols, one wouldn't be able to even figure out whether they should be looking at SATA drives or M.2 drives in the first place, and could easily waste quite a lot of time looking in the wrong place or doing comparisons that really didn't need to be done.

 

[MarkW]

I understand the features. Most people do not, and do not want to. All they care about is "Is it fast?".

 

[atheus]

Right, but if you, who understand the features (although you were off by a factor of [strike]2[/strike] 4 about M.2 x4 earlier), are telling people that they don't need to understand the features, all I can say is that is not good advice — especially when you're talking to someone who is specifically asking about them because they're actually interested in knowing.

 

[MarkW]

I read dozens of reviews every week. Somewhere in the past year, I read something somewhere that was showing an M.2 SSD pushing something in the ballpark of 650MB/sec or so. And I have read numerous articles on M.2 x4 having 32GB/sec throughput. So I just rounded the numbers down to 1000MB/sec. So when you questioned them, I went looking specifically for another M.2 review. And i found the one I posted about. So yes, I was off by 400MB/sec. I am human. I am not IBM's Watson and never will be. I was in the ballpark with a number that was a bit on the low side, but for the guy that came here asking his questions tonight, I made what he needed to understand clear. Very clear. He understands things better now than he did before he read my posts. And my posts were targeted to him. I hear zero complaints from him. I am happy.

 

[atheus]

Ok so I'm looking like a fool right now, as I was giving incorrect information all along about M.2 speeds. I was off by a factor of two, in that PCIE 3.0 lanes have 1 GB/s bandwidth per lane, not 500 MB/s per lane (500 was PCIE 2.0). This means that M.2 x4 does have 32 Gb/s (4 GB/s). Apologies!

MarkW, the Samsung SM951 M.2 x4 drive does sequential reads at 1.5-2 GB/s, and potentially will run even faster as NVMe drivers improve (since that is still only half of the bandwidth available through M.2 x4 slot). This is generally the drive that everyone uses as a standard of comparison for M.2 x4 drives.

 

[Ferrariassassin]

i am building a new PC soon and i was thinking about getting the Intel 750 PCIe card with 400Gb and i heard its the fastest storage consumers like us can buy is that true because i will buy iy soon because $350 for the fastest storage of 400GB is cheap to me. Will it be better than my Samsung 840 EVO?

 

[atheus]

i am building a new PC soon and i was thinking about getting the Intel 750 PCIe card with 400Gb and i heard its the fastest storage consumers like us can buy is that true because i will buy iy soon because $350 for the fastest storage of 400GB is cheap to me. Will it be better than my Samsung 840 EVO?

It will be immensely faster than your 840 EVO, but unfortunately that doesn't often pan out to a noticeable change in the time it takes for your computer to do the stuff you actually do in many cases.

Take a look at http://techreport.com/review/28446/samsung-sm951-pcie-ssd-reviewed/5

You'll notice that the high performance M.2/U.2 drives are basically bunched in with the SATA drives when it comes to load times — which is where you would expect them to really shine. I'm right there with you, though, in that when I build my sky lake build this fall I'd really like to use some sort of PCIE drive as my main drive, though I won't wind up doing so unless I feel that there is enough value to justify the cost. Right now a 500 GB 850 EVO is $150. An NVMe option is over double the price per gig. Perhaps the performance differences will improve with drivers, but my current impression is that it will be the next wave of NVMe devices that really put that extra bandwidth to good use for consumers.

For perspective, there are certainly applications where the M.2 drives blow SATA drives out of the water. The question is just how much time will you actually save in the long run with one vs. the other:
http://www.anandtech.com/show/9396/samsung-sm951-nvme-256gb-pcie-ssd-review/6