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
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  • chizow - Wednesday, October 28, 2009 - link

    Ya they had them for about 4 hours in an AM Shell Shocker for $240, which is their MSRP. They also had them for that price for about 8 hours at launch and since then its been gouged as high as $400 for a G2. All the other retailers that are selling for around the $240 MSRP are drop-shipping directly from Intel so they typically don't have stock in-hand and are estimating anywhere from 2-8 weeks for delivery....
  • crimson117 - Monday, October 26, 2009 - link

    Amazon has decent prices on these, but shipping time ranges from 2 weeks to 8 weeks.

    80GB G2 for $244: http://www.amazon.com/Intel-Mainstream-Solid-Retai...">http://www.amazon.com/Intel-Mainstream-...-Retail-...

    160GB G2 for $467: http://www.amazon.com/Intel-160GB-Mainstream-Retai...">http://www.amazon.com/Intel-160GB-Mains...-Retail-...

  • Xentropy - Sunday, November 1, 2009 - link

    5 days later now, and Amazon's up to $599 for the 160GB, though they are in stock instead of shipping in several weeks.
  • Exar3342 - Tuesday, October 27, 2009 - link

    I bought a G2 80GB yesturday via Amazon from a 3rd party company; was $244.00 (OEM) version. Good times.
  • strikeback03 - Monday, October 26, 2009 - link

    With your recommendation to keep at least 20% of a drive as free space, should it be within a partition, or just leave some unpartitioned space on the drive?
  • Anand Lal Shimpi - Monday, October 26, 2009 - link

    Either way works, just don't put data on it :)

    Take care,
    Anand
  • Doormat - Monday, October 26, 2009 - link

    Anand: great review.

    The 40GB 5-channel version has read speeds of 170MB/s. Does this mean that if the 10-channel G2 weren't inhibited by SATA 3Gb/s, it would probably get 340MB/s? Or is there diminishing returns on adding more channels.

    Also, any price cuts on the horizon or just stagnating until drives start shipping with SATA 6Gb/s support.
  • Anand Lal Shimpi - Monday, October 26, 2009 - link

    It's possible. All of the high end SSDs are bound by the interface for sequential read speed. I'm not sure how fast the controller could go if it weren't bound by the interface, but over 300MB/s sounds quite likely.

    Flash prices haven't really gone down lately from what I'm hearing. I don't know of any price cuts on the horizon unfortunately. Next year.

    Take care,
    Anand
  • semo - Monday, October 26, 2009 - link

    i don't think you will see any price cuts since intel can't make enough G2s.

    I tend to agree with others regarding SATA 3. If intel is not rushing to enable SATA 3 on their ICH anytime soon, why would they be coming out with SATA 3 devices?
  • ekerazha - Monday, October 26, 2009 - link

    Anand,

    it's strange to see your

    "Is Intel still my overall recommendation? Of course. The random write performance is simply too good to give up and it's only in very specific cases that the 80MB/s sequential write speed hurts you."

    of the last review, is now a

    "The write speed improvement that the Intel firmware brings to 160GB drives is nice but ultimately highlights a bigger issue: Intel's write speed is unacceptable in today's market."

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