The OCZ Vertex 3 Review (120GB)
by Anand Lal Shimpi on April 6, 2011 6:32 PM ESTThe NAND Matrix
It's not common for SSD manufacturers to give you a full list of all of the different NAND configurations they ship. Regardless how much we appreciate transparency, it's rarely offered in this industry. Manufacturers love to package all information into nice marketable nuggets and the truth doesn't always have the right PR tone to it. Despite what I just said, below is a table of every NAND device OCZ ships in its Vertex 2 and Vertex 3 products:
OCZ Vertex 2 & Vertex 3 NAND Usage | ||||
Process Node | Capacities | |||
Intel L63B | 34nm | Up to 240GB | ||
Micron L63B | 34nm | Up to 480GB | ||
Spectek L63B | 34nm | 240GB to 360GB | ||
Hynix | 32nm | Up to 120GB | ||
Micron L73A | 25nm | Up to 120GB | ||
Micron L74A | 25nm | 160GB to 480GB | ||
Intel L74A | 25nm | 160GB to 480GB |
The data came from OCZ and I didn't have to sneak around to get it, it was given to me by Alex Mei, Executive Vice President of OCZ.
You've seen the end result, now let me explain how we got here.
OCZ accidentally sent me a 120GB Vertex 2 built with 32nm Hynix NAND. I say it was an accident because the drive was supposed to be one of the new 25nm Vertex 2s, but there was a screwup in ordering and I ended up with this one. Here's a shot of its internals:
You'll see that there are a ton of NAND devices on the board. Thirty two to be exact. That's four per channel. Do the math and you'll see we've got 32 x 4GB 32nm MLC NAND die on the PCB. This drive has the same number of NAND die per package as the new 25nm 120GB Vertex 2 so in theory performance should be the same. It isn't however:
Vertex 2 NAND Performance Comparison | ||||
AT Storage Bench Heavy 2011 | AT Storage Bench Light 2011 | |||
34nm IMFT | 120.1 MB/s | 155.9 MB/s | ||
25nm IMFT | 110.9 MB/s | 145.8 MB/s | ||
32nm Hynix | 92.1 MB/s | 125.6 MB/s |
Performance is measurably worse. You'll notice that I also threw in some 34nm IMFT numbers to show just how far performance has fallen since the old launch NAND.
Why not just keep using 34nm IMFT NAND? Ultimately that product won't be available. It's like asking for 90nm CPUs today, the whole point to Moore's Law is to transition to smaller manufacturing processes as quickly as possible.
Why is the Hynix 32nm NAND so much slower? That part is a little less clear to me. For starters we're only dealing with one die per package, we've established can have a negative performance impact. On top of that, SandForce's firmware may only be optimized for a couple of NAND devices. OCZ admitted that around 90% of all Vertex 2 shipments use Intel or Micron NAND and as a result SandForce's firmware optimization focus is likely targeted at those NAND types first and foremost. There are differences in NAND interfaces as well as signaling speeds which could contribute to performance differences unless a controller takes these things into account.
The 25nm NAND is slower than the 34nm offerings for a number of reasons. For starters page size increased from 4KB to 8KB with the transition to 25nm. Intel used this transition as a way to extract more performance out of the SSD 320, however that may have actually impeded SF-1200 performance as the firmware architecture wasn't designed around 8KB page sizes. I suspect SandForce just focused on compatibility here and not performance.
Secondly, 25nm NAND is physically slower than 34nm NAND:
NAND Performance Comparison | ||||
Intel 34nm NAND | Intel 25nm NAND | |||
Read | 50 µs | 50 µs | ||
Program | 900 µs | 1200 µs | ||
Block Erase | 2 µs | 3 µs |
Program and erase latency are both higher, although admittedly you're working with much larger page sizes (it's unclear whether Intel's 1200 µs figure is for a full page program or a partial program).
The bad news is that eventually all of the 34nm IMFT drives will dry up. The worse news is that the 25nm IMFT drives, even with the same number of NAND devices on board, are lower in performance. And the worst news is that the drives that use 32nm Hynix NAND are the slowest of them all.
I have to mention here that this issue isn't exclusive to OCZ. All other SF drive manufacturers are faced with the same potential problem as they too must shop around for NAND and can't guarantee that they will always ship the same NAND in every single drive.
The Problem With Ratings
You'll notice that although the three NAND types I've tested perform differently in our Heavy 2011 workload, a quick run through Iometer reveals that they perform identically:
Vertex 2 NAND Performance Comparison | ||||
AT Storage Bench Heavy 2011 | Iometer 128KB Sequential Write | |||
34nm IMFT | 120.1 MB/s | 214.8 MB/s | ||
25nm IMFT | 110.9 MB/s | 221.8 MB/s | ||
32nm Hynix | 92.1 MB/s | 221.3 MB/s |
SandForce's architecture works by reducing the amount of data that actually has to be written to the NAND. When writing highly compressible data, not all NAND devices are active and we're not bound by the performance of the NAND itself since most of it is actually idle. SandForce is able to hide even significant performance differences between NAND implementations. This is likely why SandForce is more focused on NAND compatibility than performance across devices from all vendors.
Let's see what happens if we write incompressible data to these three drives however:
Vertex 2 NAND Performance Comparison | ||||
Iometer 128KB Sequential Write (Incompressible Data) | Iometer 128KB Sequential Write | |||
34nm IMFT | 136.6 MB/s | 214.8 MB/s | ||
25nm IMFT | 118.5 MB/s | 221.8 MB/s | ||
32nm Hynix | 95.8 MB/s | 221.3 MB/s |
It's only when you force SandForce's controller to write as much data in parallel as possible that you see the performance differences between NAND vendors. As a result, the label on the back of your Vertex 2 box isn't lying - whether you have 34nm IMFT, 25nm IMFT or 32nm Hynix the drive will actually hit the same peak performance numbers. The problem is that the metrics depicted on the spec sheets aren't adequate to be considered fully honest.
A quick survey of all SF-1200 based drives shows the same problem. Everyone rates according to maximum performance specifications and no one provides any hint of what you're actually getting inside the drive.
SF-1200 Drive Rating Comparison | ||||
120GB Drive | Rated Sequential Read Speed | Rated Sequential Write Speed | ||
Corsair Force F120 | 285 MB/s | 275 MB/s | ||
G.Skill Phoenix Pro | 285 MB/s | 275 MB/s | ||
OCZ Vertex 2 | Up to 280 MB/s | Up to 270 MB/s |
I should stop right here and mention that specs are rarely all that honest on the back of any box. Whether we're talking about battery life or SSD performance, if specs told the complete truth then I'd probably be out of a job. If one manufacturer is totally honest, its competitors will just capitalize on the aforementioned honesty by advertising better looking specs. And thus all companies are forced to bend the truth because if they don't, someone else will.
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sor - Thursday, April 7, 2011 - link
Oh sure, I agree that the bottom line is whether or not it still works, that's why they do the binning and have grades of product within that brand. If OCZ can use cheaper flash and the controller takes care of the increased failures, or the users never reach the failure threshold, then who cares, as long as the product works the same?I can't speak for the testing procedures within SpekTek or their tolerances, as I only worked for a facility that tested parts for Micron, and in the process generated the bad parts and did some of the binning before sending them to SpekTek. Much of the stuff that went to them failed our tests but was otherwise not physically damaged.
There's a reason why those parts are sold under the SpecTek brand at a discount, it shows that even the manufacturer doesn't trust them to be sold under the good brand after testing.
Panlion - Thursday, April 7, 2011 - link
I wonder if OCZ will produce a 7mm 2.5 inch drive. The newer notebooks from Lenovo are starting to demand that format it'll be nice if I can have some option other than Intel SSD.sleepeeg3 - Thursday, April 7, 2011 - link
Maintaining integrity while sticking out for the little guy, instead of bending over backward to write glowing articles for every vendor sponsor. That's what has made this site succeed.I wish you could also take OCZ to task on SandForce's controller strange tendency to lock up and vanish from a system, due to built in encryption. They are in complete denial that it is an issue, despite dozens of reports on their user forums.
edfcmc - Thursday, April 7, 2011 - link
Thank you Anand for this very informative and in-depth review of the OCZ issue and their latest 120gb vertex 3 product; especially since the 120gb products are within my price range and the size I am looking to purchase. On a side note, I have been reading your reviews since your review of the FIC PA-2007 many years ago and I love the evolution of this site and your dedication to keeping us consumers informed.p.s. Please consider asking asus/Nvidia to update the Nvidia driver on their ULV80 series as nothing new has been updated since I purchased the UL80vt based on this site's recommendation. Asus/Nvida seem to be a little non-responsive to us folks who have been requesting an update for quite some time.
ekerazha - Thursday, April 7, 2011 - link
Can't wait for reviews of SSDs (Intel G3, Crucial m4) with comparable size (120 GB).Chloiber - Thursday, April 7, 2011 - link
Anand:Just a quick note. In the newest SF-firmware, there is also still a bug with Hynid Flash. You can see it here, under "Open Issues":
http://www.ocztechnologyforum.de/forum/showthread....
"Under benchmarking scenarios with IOMETER 2006, 60GB drives that use Hynix32nm MLC (1024 blocks, 8KB pages) can impose long latencies"
Just FYI.
MarcHFR - Thursday, April 7, 2011 - link
Dear OCZ, Dear Anand,In the past, it was simple :
Vertex : always the same NAND
Agility : NAND could change
I know that Vertex name is a best seller for OCZ, but i think it will be simplier to back to this
strikeback03 - Friday, April 8, 2011 - link
That is what I was wondering, I thought the point of the Agility line was that they would use the good controller but possibly cheaper NAND.Adul - Thursday, April 7, 2011 - link
Why not make use of QOR codes so a shopper can just scan the code to be taken to a page with more detail information.miscellaneous - Thursday, April 7, 2011 - link
Given this particularly insidious paragraph:"OCZ will also continue to sell the regular Vertex 2. This will be the same sort of grab-bag drive that you get today. There's no guarantee of the NAND inside the drive, just that OCZ will always optimize for cost in this line."
Will these "grab-bag" drives be using the same SKU(s)/branding as the original - well reviewed - Vertex 2? If so, how is using the _old_ SKU(s) to identify the _new_ "grab-bag" drives, whilst introducing _new_ SKU(s) to help identify drives with the _old_ level of performance a satisfactory solution?