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Avoid SSDs with Jmicron’s JMF602 Controller

Solid state drives (SSDs) are the latest in hot tech upgrades these days, and rightly so. SSDs add huge boosts in performance to a system that is HDD bound, and the storage subsystem of a computer is the weakest link in its performance.

It's no wonder that SSDs are becoming increasingly popular. However, not all SSD drives are made alike. Don't think that you'll get great performance just by swapping out your old HDD for a new SSD. The first thing to consider is whether or not you'll want a MLC (multi-layer cell) or SLC (single-layer cell) drive. MLC SSD drives store more data, but at the cost of read and write performance, with a big dip on write performance. SLC drives rule in speed, but currently come in smaller capacities.

No matter which type of SSD you decide to pick up, you will no doubt witness instant performance gains after installing your new drive. However, with SSDs, things aren't so simple. Because of the way SSDs work, you will witness a steep degradation in performance over time. The performance occurs from a combination of things, but not because of file defragmentation like on a regular disc-based HDD.

With a regular HDD, you can simply run a good defragmentation utility to optimize the drive back to optimized conditions, and immediately experience the performance gains. On an SSD, you should never defrag the drive due to wear and tear of the flash memory cells. But this is only part of the problem. Another big problem with many SSD drives on the market is their use of the Jmicron JMF602 drive controller.

We'll just go ahead and say it right here: the controller is terrible.

First, the Jmicron JMF602 controller only has a 16 KB of onboard cache. That's barely enough to do anything. Contrary to this, the controller that Intel uses, the PC29AS21A blows the Jmicron controller out of the water with 256 KB of cache. The Intel controller also has significantly better wear leveling and write combining algorithms.

During heavy use, the Jmicron controller will literally choke on incoming data, and consequently report back to the operating system that it's buffers are filled and writes and reads need to be queued up. This puts a hold on incoming and outgoing disk I/O, causing applications to hiccup and hang while the controller chugs along. Worst, the performance degrades significantly over time as the drive is used.

Recently, OCZ swapped out the Jmicron controllers in its drives in favor of Indilink's Barefoot controller, offering significantly better performance and cell management algorithms. Other manufacturers are following suit as well.

If you're in the market for an SSD, do a bit of research to find out if the drive uses a Jmicron controller. News from Jmicron is that its updated to a new revision of its SSD controller that is suppose to solve many issues. Save yourself the problem of testing out these claims and just avoid Jmicron-based drives altogether.

  • A Stoner
    Going the way of the Dinosaur. I am still sticking with my raid-0 HDD for the foreseeable future with intermittent backups of the files I want to keep. SSD is too expensive. SSD is too new to know if it has long term problems that are as yet unknown. SSD is just popular, and I hate things that are popular, they never live up to the hype.
    Reply
  • resonance451
    SSD's will be great in the future, but I'm sticking to my 32mb cache SATA drives. I'm running a single 750gb in this system right now, and I've got great performance out of it. When I need more storage, I'll simply spring for another 750gb. Easy on the wallet and dependable, as opposed to the SSD craze.
    Reply
  • pbrigido
    For those who have done their research and purchased a SSD to fit their needs, they truly are indispensible. They are not a fad, trend, or a quick technological blip on the radar, they are here to stay. I personally have 4 64GB SLC SSDs and will never go back to a magnetic based storage solution. It is like going from modem to DSL/Cable...there is no desire to go back to the dark ages of storage solutions.
    Reply
  • baov
    No mention of samsung and it's arm controler?

    Also, it's the intel drive that has its performance reduced significatly over time because of it's complex wear-leveling algorithm. Moreso than the rest. http://pcper.com/article.php?aid=669
    Reply
  • A Stoner
    pbrigidoFor those who have done their research and purchased a SSD to fit their needs, they truly are indispensible. They are not a fad, trend, or a quick technological blip on the radar, they are here to stay. I personally have 4 64GB SLC SSDs and will never go back to a magnetic based storage solution. It is like going from modem to DSL/Cable...there is no desire to go back to the dark ages of storage solutions.So, you have upwards of $1600 to toss into your storage devices. most people have about $1000 for their rig, sometimes more, sometimes less. SLC is the most expensive per megabyte, so I know you are paying less than $400 a pop for those, especially if you have had them long enough to become addicted to them.

    They are great, wonderful, not fads and I will one day likely move to them or something that replaces them. For today though, they are not reliable, they are advancing too fast for me to spend the cash for one today that may be 1/4 the speed, storage space and longevity of one I could have paid half price for 6 months from now. For people with unlimited cash for these toys, they are well worth the cash, but for people who have more modest means, or just modest personalities, I think HDD is the way to go, today.
    Reply
  • campiosa
    There are alot more factors that go into an SSD's performance than just the controller. Mostly the problems arise from Windows not being optimized for SSD technology. The most common cause of the I/O "choke" is from improper partition alignment and can be easily fixed before the OS is installed. I am currently using a Jmicron controlled SSD and its performance is great.

    http://www.ocztechnologyforum.com/forum/forumdisplay.php?f=186 is a great place for info on SSD changes and tweaks to get the best performance from your device.
    Reply
  • pbrigido
    Actually I've spent around $2,000 for my SLC SSDs. Like I said though, a SSD is a need based storage solution. For those who have the money and a need for this type of storage, a SSD is perfect. For those who don't, a traditional HD would work just fine.
    Reply
  • john_smarty
    hdd is old technology. sometime soon it has to be replaced. but i dont think that ssd's are going to be the ones to do it.
    Reply
  • A Stoner
    pbrigidoActually I've spent around $2,000 for my SLC SSDs. Like I said though, a SSD is a need based storage solution. For those who have the money and a need for this type of storage, a SSD is perfect. For those who don't, a traditional HD would work just fine.I agree with you. If you really do need that speed, and you make money off your computer, then it is the way to go, and replacing them a year from now with higher performing ones would be economically worth while. I guess we are in two different levels of the computer usage model. I am just a home user commenting on rigs, typically for things like gaming, and you seem to be a professional who might be into database management or something else that is heavily taxing on the storage system.
    Reply
  • Gian124
    @ baov,

    Awesome article, thank you for linking that!!!
    Reply