Aftermarket SSD On A MacBook Pro: TRIM Gets Tested

Enabling TRIM Is Almost Always Worth It

We've spent a lot of time talking to storage professionals, including some from LSI, who agree that TRIM is beneficial, even when your controller is designed to make the most of free space on an SSD. So, if a SandForce-based drive can see some benefit, so will any other solid-state repository you install. Consequently, it's worth it to get TRIM working, even when Apple tries to keep you from the command artificially.

To what end does TRIM matter? Well, our AJA System Test and DiskTester benchmarks show that the explicit performance gains, even in a synthetic, are pretty small. In the real world, you probably wouldn't notice one way or the other. But sure, turn TRIM on and things speed up a little bit. 

Source: LSI/SandForceSource: LSI/SandForce

More important are the endurance-oriented reasons to keep TRIM turned on. Without the command, your operating system knows when data is deleted, but has no way to tell the SSD's controller. In turn, the SSD keeps moving that information around via garbage collection, unnecessarily programming and erasing the flash memory cells with stale data. This means that, at some point, the SSD will fill up with data, leaving the controller only with over-provisioned flash with which to work. That's seven to 12% of most desktop SSDs, and includes the space for firmware features like bad block replacement.

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  • osamabinrobot
    i think you have an issue with your benchmark graphs, both trim enabled say fresh state
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  • osamabinrobot
    i think you have an issue with your benchmark graphs, both trim enabled say fresh state
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  • steamingabe
    Any chance you did any real world benchmarks with the stock 500gb drive as well as the 840 Pro?
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  • halcyon
    My hat is off to the author for the first 3 paragraphs, to say the least. I'm not sure where I've seen this more succinctly...more clearly explained.

    Ah, Apple. Why must it be a love-hate relationship? Clearly, you make some awesome hardware but your pricing and closed-mindedness is @$$munch. You disable TRIM if one doesn't pay 50 to 75% more for one of your lower-performing (than the typical aftermarket piece) OEM SSDs. Shame on you. Greedy bastards. Get with it or continue to decline. It's good to see in the case of TRIM Apple's @$$munchiness is so mindlessly circumvented. ...and to think I once gave them a bunch of my money. 4" Apple...4"
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  • crisso2face
    I wish it would be that easy. But its not. The problem with the OS X Trim command it that it kills your SSD. I fried 3 SSD Samsung 840 ( not the pro version ). Im at my 4-th right now ( thx God for warranty ). I work in a laptop store service. So I deal with a lot of laptops on a daily basis. This isn't my firs run in with SSD's. Cant really explain it, not an OS X expert. As soon as I turn on trim, with in a month or so, my SSD dies. This is my personal laptop. As I was saying, I work in a service, I have tech guys which are very good at what they do. If it were a motherboard problem, they would have found it. Its not the laptop ( MacBook Pro 17" Mid 2010 I5, nVidia 330M ). I can't really prove it, I my self, am a guy that needs hard proof, but this isn't a coincidence. 3 SSD's. I just recently had 2 customers with a macbook that asked me to upgrade to an SSD. They both came back to me in a month and a half with a fired SSD. After replacing them i hadn't turned on trim anymore. It's been 3 moths since, and they haven't returned since. Right now I myself use a 4-th SSD Samsung 840 without trim enabled. Haven't had a problem since. You do the math.
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  • ojas
    Hey, you know what i'd really like to see? How to enable TRIM/AHCI when you have a MacBook running Windows.

    I installed Windows directly, then performed some magic to install bootcamp drivers later, but the problem was that the EFI in Apple PCs disable AHCI when running Windows.

    Now Intel'ss SSD toolbox can still perform TRIM even when it's IDE mode (apparently) but i wasn't sure, so i had to Google a solution.

    Currently i have to enter four console commands in a GRUB menu before i can boot into Windows over AHCI, and BootCamp doesn't like it when i do.

    It's annoying, because i don't know much Linux, and i have no idea how to enable the GRUM menu or some sort of automated boot script that enters those commands for me.

    Commands:
    setpci -d 8086:2828 90.b=40
    set root=(hd0,1)
    chainloader +1
    boot
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  • ssdpro
    There is a big question here: Why does Apple intentionally disable TRIM on non-OEM drives? Think long term - why would Apple, who controls the testing/firmware on OEM storage, know they need to disable TRIM on all 3rd party drives? Are they preventing a problem that is exposed after long term usage of TRIM hacks with their EFI/SMC/OSX code?

    Look at crisso2faces comments above - I see that all the time on drives from multiple manufacturers, not just Samsung. Is seeing a couple extra MB/s in a benchmark worth gambling with possible catastrophic failure because you aren't using the system as designed?
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  • TheCapulet
    I agree with SSDPro. I know a lot of AppleCare Advisors, so I know first hand how terribly limited Apple Computers are. But the fact of the matter is... it simply comes down to this: If you want "advanced"(lol) features like TRIM support, don't buy an Apple computer.

    If you bought a Mac without doing research into your own required features, return it. If you're past your 15 days, look at it as a lesson learned. Macs aren't for everyone. Realistically, Macs aren't for anyone aside from people who want the most watered down experience possible, but the pro apps keep people in line for computers that don't really fit their needs.
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  • crisso2face
    The problem with trim on mac is that it has something to do with the comand it self that is sent from the OS X. From what I heard so far, it appears that the command is designed for a limited nr of drives. It has somthing to do with the timing and the blocks or cells of the SSD. The Trim comand of OS X is design for those specific drives. Repecing them with difrent 3rd party drives could prove catastrophic. I dont really understand how that works, up until now i bealived that the comand is basicly the same, no mater of the OS you use. As it turns out ( and i am not yet completely convinced of this ), the comand for trim is NOT the same for all OS's. Apparantly OS X tells the drive to do the trim in some different way, and that wers out the drive very very fast end eventually it dies out. Like I said. Im not an expert, but somthing obviously happens with the drives once you enable trim. Unfortunately I cant take the chance anymore.
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  • rojjr
    I am using a 256GB Samsung 830 Pro in a late 2011 iMac using TRIM enabler and I haven't had any problems in 8 months. Before I had this same drive in a 2009 iMac and it performed well also. *fingers crossed*
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  • jameskatt
    The biggest argument I have against enabling TRIM is that TRIM is a SATA-only command.

    SSDs attached via PCIe, USB 3.0, FireWire, or Thunderbolt cannot receive the TRIM command. Macs won't even recognize them as SSDs nor would the Mac send them the TRIM command even if it is enabled.

    The newest MacBooks now use PCIe SSDs.

    SSDs (such as OWC Mercury SSDs with SandForce controllers) have evolved to the point they don't need TRIM - particularly when the SSDs are not attached via SATA? They do their own garbage-collection and optimization.

    OWC - in particular - advises against enabling TRIM on their Sandforce controller OWC Mercury SSDs since this increases wear and tear on their SSDs. TRIM adds extra unnecessary writes when the SSD already did this on its own. Enabling TRIM would essentially harm the SSD and shorten its lifespan. http://blog.macsales.com/11051-to-trim-or-not-to-trim-owc-has-the-answer

    If modern SSDs need TRIM, they would be in danger of serious performance problems if the SSD was attached via a non-SATA connection such as USB 3.0 or PCIe or Firewire or Thunderbolt. Unless the manufacturer insures their SSD's controller does its own version of TRIM, then they would suffer serious performance problems when attached via non-SATA connection compared to the competition.

    This is why I argue that TRIM is currently useless in modern SSDs.
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  • RobLewis
    More modern systems may behave differently, but when I upgraded an early-2008 MacBook pro with a SATA I 256GB SSD from Kanguru, it worked great at first but got steadily slower and slower until I was considering putting the original hard drive back in. Trim Enabler completely turned the situation around and the SSD is back to being as snappy as ever.
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  • RobLewis
    More modern systems may behave differently, but when I upgraded an early-2008 MacBook pro with a SATA I 256GB SSD from Kanguru, it worked great at first but got steadily slower and slower until I was considering putting the original hard drive back in. Trim Enabler completely turned the situation around and the SSD is back to being as snappy as ever.
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