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
OCZ Tries Again with the Vertex
This is Ryan Petersen:
He’s the CEO of OCZ Technology. He wasn’t too happy after my Intel X25-M SSD review.
Although that review was about the X25-M, it addressed a major shortcoming with a number of other SSDs in the market - the most popular at the time being OCZ’s Core line.
The problem with the Core line was that although they were competitively priced, they had a major performance issue: small file write latency. The problem manifested itself in system-wide stuttering during disk intensive multitasking. It wouldn’t take a lot to make those drives stutter, and until that article went live, everyone assumed that the problem was Windows, the disk controller, or something else.
I placed the blame on the drives and Ryan wasn’t all too happy.
We argued. A lot. He claimed it was unfair that I was comparing the Core series to Intel’s far more expensive X25-M; I argued that the user experience offered by his drives was inferior to that of a regular hard drive. We never really saw eye to eye on SSDs after that article.
Ryan told me the problem was a lack of cache, and that they’d have a future version of their SSD with a large off-chip DRAM cache. Ryan did not want to send me any more SSDs that didn’t have a cache on them. It wasn’t just OCZ, we had difficulty getting JMicron based SSDs from most manufacturers after that article. Manufacturers were pissed.
I offered to look at any new SSDs they had coming, regardless of who made the controller. But I made one thing very clear - I did not believe that the JMicron based drives were fit for sale. I felt that they were hurting the image of SSDs in the market and doing more harm than good. Ask any of the major players in the flash and OS industries and you’ll hear the same complaint. We need good SSDs in the market, not a mixture of great ones and bad ones.
In early December I got word from OCZ that their first drive with a DRAM cache was nearing final production. The controller was from a Korean company called Indilinx, with a number of ex-Samsung engineers. JMicron was out for this product, they didn’t have a suitable controller - the JMF602B was it. I won’t draw too much attention to the fact that if the JMF602B drives were indeed fine then there would be no need to consider another controller manufacturer.
The Indilinx Barefoot controller would support up to 64MB of off-chip DRAM, but have no on-die cache. All user data would be buffered in this memory. Now 64MB is more than enough to handle anything being written to the drive, but the memory is also used for the ARM7 based processor for its work in dealing with wear leveling and flash block cleaning (removing invalid pages).
There’s a key distinction here between the Barefoot and Intel’s controller - the X25-M doesn’t store any user data in its DRAM. Technically the Barefoot approach is no less prone to dataloss than a standard hard drive, but the Intel approach is a bit better. In the event of sudden power loss there’s a chance that some of the data in the Barefoot’s 64MB buffer could be lost before it’s committed to flash.
The OCZ Vertex drive would have a more heavy duty controller, with an ARM processor and a large off-chip DRAM to improve performance. To top it all off, OCZ would sell it at a price much lower than Intel’s X25-M. Could this finally be the affordable SSD we’ve been looking for?
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Luddite - Friday, March 20, 2009 - link
So even with the TRIM command, when working with large files, say, in photoshop and saving multiple layers, the performance will stil drop off?proviewIT - Thursday, March 19, 2009 - link
I bought a Vertex 120GB and it is NOT working on my Nvidia chipsets motherboard. Anyone met the same problem? I tried intel chipsets motherboard and seems ok.I used HDtach to test the read/write performance 4 days ago, wow, it was amazing. 160MB/s in write. But today I felt it slower and used HDtach to test again, it downs to single digit MB per second. Can I recover it or I need to return it?
kmmatney - Thursday, March 19, 2009 - link
Based on the results and price, I would say that the OCZ Vertex deserves a Editor's choice of some sort (Gold, Silver)...Tattered87 - Thursday, March 19, 2009 - link
While I must admit I skipped over some of the more technical bits where SSD was explained in detail, I read the summaries and I've gotta admit this article was extremely helpful. I've been wanting to get one of these for a long time now but they've seemed too infantile in technological terms to put such a hefty investment in, until now.After reading about OCZ's response to you and how they've stepped it up and are willing to cut unimportant statistics in favor of lower latencies, I actually decided to purchase one myself. Figured I might as well show my appreciation to OCZ by grabbing up a 60GB SSD, not to mention it looks like it's by far the best purchase I can make SSD-wise for $200.
Thanks for the awesome article, was a fun read, that's for sure.
bsoft16384 - Thursday, March 19, 2009 - link
Anand, I don't want to sound too negative in my comments. While I wouldn't call them unusable, there's no doubt that the random write performance of the JMicron SSDs sucks. I'm glad that you're actually running random I/O tests when so many other websites just run HDTune and call it a day.That X25-M for $340 is looking mighty tempting, though.
MrSpadge - Thursday, March 19, 2009 - link
Hi,first: great article, thanks to Anand and OCZ!
Something crossed my mind when I saw the firmware-based trade-off between random writes and sequential transfer rates: couldn't that be adjusted dynamically to get the best of both worlds? Default to the current behaviour but switch into something resembling te old one when extensive sequential transfers are detected?
Of course this neccesiates that the processor would be able to handle additional load and that the firmware changes don't involve permanent changes in the organization of the data.
Maybe the OCZ-Team already thought about this and maybe nobody's going to read this post, buried deep within the comments..
MrS
Per Hansson - Thursday, March 19, 2009 - link
Great work on the review AnandI really enjoyed reading it and learning from it
Will there be any tests of the old timers like Mtron etc?
tomoyo - Thursday, March 19, 2009 - link
That was kind of strange to me too. But I assume Anand really means the desktop market, not the server storage/business market. Since it's highly doubtful that the general consumer will spend many times as much money for 15k SAS drives.Gary Key - Thursday, March 19, 2009 - link
The intent was based it being the fastest for a consumer based desktop drive, the text has been updated to reflect that fact.tomoyo - Thursday, March 19, 2009 - link
I've always been someone who wants real clarify and truth to the information on the internet. That's a problem because probably 90% of things are not. But Anand is one man I feel a lot of trust for because of great and complete articles such as this. This is truly the first time that I feel like I really understand what goes into ssd performance and why it can be good or bad. Thank you so much for being the most inciteful voice in the hardware community. And keep fighting those damn manufacturers who are scared of the facts getting in the way of their 200MB/s marketing bs.