Testing TRIM

A firmware update gives you TRIM support, but we should probably test to make sure it's actually working.

First up, the Intel X25-M G2 with the TRIM firmware. I ran a 4KB random write test across the entire 80GB LBA space for five minutes. I ran the test again afterwards and recorded the average transfer rate for each run:

4KB Random Write, IOQ=16 Run 1 Run 2
Intel X25-M 80GB TRIM Firmware 37.9 MB/s 13.8 MB/s


As expected, performance goes down as the drive fills up. The second run is much slower than the first.

Now look at the two runs if we format the drive in between. The format under Windows 7 triggers a TRIM of all invalid data, meaning all the jibberish we generated in the first run is gone and the second run now runs at full speed:

4KB Random Write, IOQ=16 Run 1 Run 2 after Format
Intel X25-M 80GB TRIM Firmware 37.9 MB/s 38.0 MB/s


Obviously you don’t usually write a bunch of garbage to your drive then format and repeat, but we’re trying to confirm that TRIM works here; it does. Windows 7 will actually take noticeably longer to format a drive that supports TRIM and has data on it. It still completes in less than 30 seconds on these SSDs, but it's a lot longer than the few seconds it used to take before TRIM.

This confirms that TRIM works on a format, but what about if you delete a partition? To find out I created a partition on my X25-M G2, filled it with data, deleted the partition and ran my 4KB random write test across all LBAs. If deleting a partition forces TRIM I should see new-performance out of the G2:

4KB Random Write, IOQ=16 Run 1 Run 2 after Deleting Partition
Intel X25-M 80GB TRIM Firmware 37.9 MB/s 17.9 MB/s


Performance drop. Formatting a partition causes the contents to be TRIMed, but just deleting a partition doesn’t. This means if you accidentally delete a partition you can still retrieve your data, however there’s no way to go back from a format.

What about file deletion? I performed the same test. Created a partition, filled it with garbage but then deleted the garbage before deleting the partition and running my 4KB random write test. Deleting data should force a TRIM:

4KB Random Write, IOQ=16 Run 1 Run 2 after Deleting All Files
Intel X25-M 80GB TRIM Firmware 37.9 MB/s 40.4 MB/s


Indeed it does. You no longer have to worry about performance dropping over time. When you delete a file it’ll eventually be nixed on the SSD as well. Below we have the actions that will force a TRIM of data under Windows 7:

Windows 7 File Delete Partition Format Partition Delete
TRIM? Yes Yes No


Formatting your drive now actually does something. You no longer have to boot to DOS and secure erase your SSD before installing Windows, just quick format the partition before installing Windows 7.

I performed the same tests on an Indilinx MLC based SSD, this time a SuperTalent UltraDrive GX with the 1819 TRIM-enabled firmware. The results were identical:

4KB Random Write, IOQ=16 Run 1 Run 2 After Format After File Delete
SuperTalent (Indilinx) UltraDrive GX TRIM Firmware v1819 17.8 MB/s 14.1 MB/s 17.8 MB/s 17.8 MB/s


We have TRIM working on both Indilinx (from SuperTalent/OCZ) and Intel drives. Sweet.

Index Wipe When You Can’t TRIM


View All Comments

  • DanH - Monday, October 26, 2009 - link

    Do what I did. Buy a Gen 2, clone your drive, and sell the Gen 1 on ebay while it's still worth as much as it is. You will easily get close to $200 for the 80 gig version. I lost $30 upgrading, which was very worth it for TRIM support and the newest hardware. Reply
  • masouth - Wednesday, November 18, 2009 - link

    I must be misunderstanding you so please let me make sure I have this right...

    Someone bought your USED G1 for $30 less than you paid for your NEW G2!?!

    A sucker born every minute.
  • mwaschkowski - Monday, October 26, 2009 - link

    what cloning software did you use?

    I guess I couldn't switch to another SSD at the same time due to needing to clone the drive and using the same drivers between both SSDs?
  • DanH - Monday, October 26, 2009 - link

    I used Carbon Copy Cloner on the mac, but Acronis TrueImage would work fine on PC. Reply
  • chizow - Monday, October 26, 2009 - link

    Acronis True Image is probably the easiest for Windows, especially if you're cloning to identical sized drives. With the trial you can do this for free, I believe Seagate and WD have simplified free versions if you have one of their drives installed.

    Don't mess with any of the backup/restore options, go to the Utilities and choose Clone drive, then select destination and source drives. Takes about 10-20 minutes depending how much data you have and is effortless.
  • mwaschkowski - Tuesday, October 27, 2009 - link

    OK, Thanks!! Reply
  • pcfxer - Tuesday, October 27, 2009 - link

    sudo dd if=/dev/da0 of=/dev/da1

    Boot up into Knoppix and it is legitimately free.
  • Concillian - Wednesday, October 28, 2009 - link

    No kidding. I clone my drive every once in a while on my fileserver with dd. Why it's made so difficult in every other OS is beyond me. I really shouldn't need to buy software in order to make a copy. It's a pretty basic function, really. Reply
  • Griswold - Thursday, November 19, 2009 - link

    Just that the aforementioned software isnt primarily a cloning software but a backup and image software. Cloning a disk is just a minor function of it. And no, cloning a disk isnt a worthwhile backup strategy for most people.

    That said, I backup my system and data on a daily basis, but I only clone a drive once maybe twice a year. I wouldnt mind if it was built into windows, but its far from a necessity.
  • Taft12 - Monday, October 26, 2009 - link

    This is nothing new, it has been well known for many years that there is a price to pay by being an early adopter. Reply

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