Gadgetory

hey one this is Steve from gamers Nexus Donna and I am here with Kent Smith from LSI and we are here to talk about the Sanford's controllers and SSD controllers in general Kent can you tell us a little bit more about what you do here at LSI sure I'm the senior director of outbound marketing for LSI and specifically I focus on the SandForce controllers and the technology we have so when when consumers are looking at the SSD market today you obviously see various capacities on the drives to 40 gigabytes 256 gigabytes we've talked a little bit about over-provisioning and how that affects capacity and why it's important can you tell us more about over-provisioning and why consumers should care about it absolutely it's a it's a very misunderstood concept over-provisioning is very important because the the capacity that the SSD has in spare or that which is over provisioned is very important during garbage collection and so if an SSD is giving all the capacity to the user there's no spare area for it to do its recycling and what happens is it slows down in that period so if you take a small portion of the user space let's say 7% you can typically get back a much larger improvement in performance usually on the order of 20% or more and in fact last year at the flash memory summit I did a whole presentation just on this very topic and so that's actually available online and you can look at your your your users could look at that and see more details behind that um but also you know just on the client side typically you'll have like a 7% difference but to really understand how much you can improve performance and enterprise SSD will oftentimes take as much as 28% of that user space and give it in the form of over provisioning so instead of 256 gigs you might see a 200 gigabyte Drive and so you know a lot of people say hey you're stealing gigabytes from me you know and it's funny when I see that because those enterprise SSDs are Tremaine higher in performance you know a 28% reduction in userspace could equate to a 50% or higher performance improvement so users shouldn't think they're losing anything they're getting it in speed and performance and that's really the reason for SSDs in the first place so one of the key differentiators force and force from what I understand is dira right and can you tell us a little bit more about this technology and what it does and why it's relevant to consumers yeah sure adder right is actually a very unique feature force and force controllers introduced back when we first introduced our first controller and again just like over-provisioning a lot of people don't really understand what it's doing and and how it benefits users the entropy which is kind of the the randomness of the data if you have a relatively low entropy file you can reduce its size on the SSD and so the advantage of that is directly related to what we were just talking about for over-provisioning so if I had let's say 50 gigabytes worth of data and I could make it physically fit into 25 gigabytes I then have another 25 gigabytes of over-provisioning and we were just talking about how you can take a little amount of user space and it translates into a huge performance gain and that also is what dira writes doing so they're very interrelated and so if you had an SSD with relatively typical entropy you can gain a tremendous performance advantage and so that's what a lot of benchmarks show when you when you run them with some of the real world benchmarks you see a lot of real-world entropy and so that's really what you're gonna see when you get the drive and start using it on its own if you take a more synthetic benchmark it depends on how much entropy that benchmark has so if it's not very compressible if it's completely randomized data the benchmark is gonna look pretty bad on a sand force drive and so people will say oh see that's what I could Specht my data is all you know high entropy I have a lot of MPEG data SSD is generally comprised of a combination of different entropy types especially when it's your boot drive so if you have a system you're booting from that SSD the operating system itself takes a lot of capacity and that has a huge advantage with dira right so a lot of your capacity is already already going to be condensed and even if you were to give a hundred percent entropy after that on top of the OS you're still gonna have quite a bit of game so again if you if you take benchmarks that synthetically are just looking at high entropy data you're never gonna actually see that in the real world so Durrett is a huge advantage for for SSDs all the SandForce SSDs have that capability and you know when you test with a real-world benchmark you can really see its advantages there's another area that's really important for SSDs and that's right amplification and there's there's again a lot of people that are sort of confused over that whole area and so write amplification first introduced by Intel and other companies back in the early early 2009 and then later sent first introduced a write amplification of actually less than one and so the idea behind ratification is you send so much information to a hard disk drive and that data is written directly to the hard disk drive so it doesn't have an idea of a right amplification because what gets read from the host to the hard disk drive is written directly on an SSD because it's using NAND flash it has to be moved around during what's called garbage collection and so the the problem is that when you write from the host to the SSD you actually have to move that data multiple times so you're writing in an amplified form so what you write to the flash is many times greater than you rode from the host and so you get this right application factor now there's many things that affect it when you write sequentially you can keep a relatively low write amplification when you write randomly you get a really high number now most people wouldn't care about this except SSDs have a limited write cycle because of the flash memory so the more times you write to it the shorter its life will be so you want to keep your write amplification down as low as possible now in general you can't really control it you know there's not things you can do hey I'm gonna I'm gonna stop writing certain data yeah that would be ridiculous what's the point of that so what you need is technologies that can take advantage of it and in fact the the LSI SandForce technologies like dura right have a huge advantage in this area the capability of Dura right can actually reduce the write amplification less than one because of its data reduction technology you write less data in the first place so then when you're garbage collecting and it's moving that data around it takes actually quite a bit of time before it ever equates to the original size and so you have a huge advantage your drives lasts much longer and again that's only available if you're using a an LSI SandForce controller in your SSD