The SSD Anthology: Understanding SSDs and New Drives from OCZ
by Anand Lal Shimpi on March 18, 2009 12:00 AM EST- Posted in
- Storage
Once More, With Feeling
Ryan said we’d lose some sequential write performance. The drive would no longer be capable of 230MB/s writes, perhaps only down to 80 or 90MB/s now. I told him it didn’t matter, that write latency needed to come down and if it were at the sacrifice of sequential throughput then it’d be fine. He asked me if I was sure, I said yes. I still didn’t think he could do it.
A couple days later and I got word that OCZ just got a new firmware revision back from Korea with the changes I’d asked for. They were going to do a quick test and if the results made me happy, they’d overnight a drive to me for Saturday delivery.
He sent me these iometer results:
The New Vertex was looking good, but was it too good to be true?
I couldn’t believe it. There was no way. “Sure”, I said, “send the drive over”. He asked if I’d be around on Saturday to receive it. I would be, I’m always around.
This was the drive I got:
No markings, no label, no packaging - just a black box that supposedly fixed all of my problems. I ran the iometer test first...it passed. I ran PCMark. Performance improved. There’s no way this thing was fixed. I skipped all of the other tests and threw it in my machine, once again cloning my system drive. Not a single pause. Not a single stutter.
The drive felt slower than the Intel or Summit drives, but that was fine, it didn’t pause. My machine was usable. Slower is fine, invasive with regards to my user experience is not.
I took the Vertex back out and ran it through the full suite of tests. It worked. Look at the PCMark Vantage results to see just what re-focusing on small file random write latency did to the drive’s performance:
The Vertex went from performing like the OCZ Apex (dual JMicron JMF602B controllers) to performing more like an Intel X25-M or OCZ Summit. I’ll get to the full performance data later on in this article, but let’s just say that we finally have a more affordable SSD option. It’s not the fastest drive in the world, but it passes the test for giving you the benefits of a SSD without being worse in some way than a conventional hard drive.
As the Smoke Cleared, OCZ Won Me Over
Now let’s be very clear what happened here. OCZ took the feedback I gave them, and despite it resulting in a product with fewer marketable features implemented the changes. It’s a lot easier to say that your drive is capable of speeds of up to 230MB/s than it is to say it won’t stutter, the assumption is that it won’t stutter.
As far as I know, this is the one of the only reviews (if not the only) at the time of publication that’s using the new Vertex firmware. Everything else is based on the old firmware which did not make it to production. Keep that in mind if you’re looking to compare numbers or wondering why the drives behave differently across reviews. The old firmware never shipped thanks to OCZ's quick acting, so if you own one of these drives - you have a fixed version.
While I didn’t really see eye to eye with any of the SSD makers that got trashed in the X25-M review, OCZ was at least willing to listen. On top of that, OCZ was willing to take my feedback, go back to Indilinx and push for a different version of the firmware despite it resulting in a drive that may be harder to sell to the uninformed. The entire production of Vertex drives was held up until they ended up with a firmware revision that behaved as it should. It’s the sort of agility you can only have in a smaller company, but it’s a trait that OCZ chose to exercise.
They were the first to bring an Indilinx drive to the market, the first to produce a working drive based on Samsung’s latest controller, and the company that fixed the Indilinx firmware. I’ve upset companies in the past and while tempers flared after the X25-M review, OCZ at least made it clear this round that their desire is to produce the best drive they could. After the firmware was finalized, OCZ even admitted to me that they felt they had a much better drive; they weren’t just trying to please me, but they felt that their customers would be happier.
I should also point out that the firmware that OCZ pushed for will now be available to all other manufacturers building Indilinx based drives. It was a move that not only helped OCZ but could help every other manufacturer who ships a drive based on this controller.
None of this really matters when it comes to the drive itself, but I felt that the backstory was at least just as important as the benchmarks. Perhaps showing you all a different side of what goes on behind the scenes of one of these reviews.
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SkullOne - Wednesday, March 18, 2009 - link
Fantastic article. Definitely one of the best I've read in a long time. Incredibly informative. Everyone who reads this article is a little bit smarter afterwards.All the great information about SSDs aside, I think the best part though is how OCZ is willing to take blame for failure earlier and fix the problems. Companies like that are the ones who will get my money in the future especially when it is time for me to move from HDD to SSD.
Apache2009 - Wednesday, March 18, 2009 - link
i got one Vertex SSD. Why suspend will cause system halt ? My laptop is nVidia chipset and it is work fine with HDD. Somebody know it ?MarcHFR - Wednesday, March 18, 2009 - link
Hi,You wrote that there is spare-area on X25-M :
"Intel ships its X25-M with 80GB of MLC flash on it, but only 74.5GB is available to the user"
It's a mistake. 80 GB of Flash look like 74.5GB for the user because 80,000,000,000 bytes of flash is 74.5 Go for the user point of view (with 1 KB = 1024 byte).
You did'nt point out the other problem of the X25-M : LBA "optimisation". After doing a lot of I/O random write the speed in sequential write can get down to only 10 MB /s :/
Kary - Thursday, March 19, 2009 - link
The extra space would be invisible to the end user (it is used internally)Also, addressing is normally done in binary..as a result actual sizes are typically in binary in memory devices (flash, RAM...):
64gb
128gb
80 GB...not compatible with binary addressing
(though 48GB of a 128GB drive being used for this seems pretty high)
ssj4Gogeta - Wednesday, March 18, 2009 - link
Did you bother reading the article? He pointed out that you can get any SSD (NOT just Intel's) stuck into a situation when only a secure erase will help you out. The problem is not specific to Intel's SSD, and it doesn't occur during normal usage.MarcHFR - Wednesday, March 18, 2009 - link
The problem i've pointed out has nothing to do with the performance dregradation related to the write on a filled page, it's a performance degradation related to an LBA optimisation that is specific to Intel SSD.VaultDweller - Wednesday, March 18, 2009 - link
So where would Corsair's SSD fit into this mix? It uses a Samsung MLC controller... so would it be comparable to the OCZ Summit? I would expect not since the rated sequential speeds on the Corsair are tremendously lower than the Summit, but the Summit is the closest match in terms of the internals.kensiko - Wednesday, March 18, 2009 - link
No, OCZ Summit = newest Samsung controller. The Corsair use the previous controller, smaller performance.VaultDweller - Wednesday, March 18, 2009 - link
So what's the difference?The Summit is optimized for sequential performance at the cost of random I/O, as per the article. That is clearly not the case with the Corsair drive, so how does the Corsair hold up in terms of random I/O? That's what I'm interested in, since the sequential on the Corsair is "fast enough" if the random write performance is good.
jatypc - Wednesday, March 18, 2009 - link
A detailed description of how SSDs operate makes me wonder: Imagene hypothetically I have a SSD drive that is filled from more than 90% (e.g., 95%) and those 90% are read-only things (or almost read-only things such as exe and other application files). The remaining 10% is free or frequently written to (e.g., page/swap file). Then the use of drive results - from what I understood in the article - in very fast aging of those 10% of the SSD disk because the 90% are occupied by read-only stuff. If the disk in question has for instance 32GB, those 10% are 3.2 GB (e.g., a size of a usual swap file) and after writing it approx. 10000 times, the respective part of the disk would become dead. Being occupies by a swap file, this number of reads/writes can be achieved in one or two years... Am I right?