TRIM Functionality

SandForce has always exhibited strange behavior when it came to TRIM. Even Intel's custom firmware in the SSD 520 wasn't able to fix SandForce's TRIM problem. The issue happens when the SSD is completely filled with incompressible data (both user LBAs and spare area). Any performance degradation after that point won't be restored with a TRIM pass and instead will require a secure erase to return to new. None of the Intel SF SSDs have been able to fix this issue and the 525 is no exception. I ran a slightly modified version of our usual test here. I filled the drive with incompressible data, ran our consistency workload (also with incompressible data) then measured performance using a 128KB (incompressible) pass in IOmeter. I then TRIMed the entire drive and re-ran the IOmeter test.

Intel SSD 525 Resiliency - IOMeter 128KB Incompressible Sequential Write
  Clean After Torture (30 mins) After TRIM
Intel SSD 525 240GB 293.5 MB/s 59.8 MB/s 153.3 MB/s

And the issues persists. This is really a big problem with SandForce drives if you're going to store lots of incompressible data (such as MP3s, H.264 videos and other highly compressed formats) because sequential speeds may suffer even more in the long run. As an OS drive the SSD 335 will do just fine since it won't be full of incompressible data, but I would recommend buying something non-SandForce if the main use will be storage of incompressible data.

Power Consumption

Idle power consumption is appreciably lower on the 525 than on the 520, however it's still not as low as the latest from Samsung. According to SandForce, a newer silicon spin of the SF-2281 controller exists that drives idle power consumption down even lower however most drive makers haven't chosen to implement it. Intel confirmed that it's still using the same silicon as the 525, so all improvements here are purely due to firmware.

Despite the gains in idle power consumption, I did measure consistently higher power consumption under active workloads. The gains at idle are more important to improving battery life, although I would liked to have seen reductions across the board. Even more, if SandForce has newer, lower power silicon available I'd like to see that used as well. SandForce tells me that its new low power SF-2281 revision is mostly used by OEMs at this point, not channel drive vendors.

Update: We've measured 525 power consumption using the 3.3V rail supplied directly to the drive.

Drive Power Consumption - Idle

Drive Power Consumption - Sequential Write

Drive Power Consumption - Random Write

AnandTech Storage Bench 2011 - Light Workload Final Words
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  • vcorem - Wednesday, January 30, 2013 - link
  • IanCutress - Wednesday, January 30, 2013 - link

    Mushkin uses a stacked daughter board to achieve 480GB. This is usually ok in a motherboard, but not in a z-height limited mobile device. While it's still electrically mSATA, it is technically outside the mSATA specifications which limit z-height (if I recall correctly).
  • lukarak - Wednesday, January 30, 2013 - link

    What is the chip density in the 768 GB SSD board in a rMBP? Does it have 12?
  • Kristian Vättö - Wednesday, January 30, 2013 - link

    Yup, the 768GB SSD in rMBP has twelve 64GB (8x8GB) packages.

    However, SandForce has much stricter restrictions, the SF-2281/2 can only access up to 64 NAND dies (that's up to 512GB with 8GB dies). Samsung could build a 1TB drive if they wanted to, they just don't see the market for it (yet).
  • lukarak - Wednesday, January 30, 2013 - link

    Thanks for the answer.

    On a slightly related note, the iPad (late 2012) 16 GB, has a single NAND chip, as could be seen in the teardowns, and there doesn't seem to be any room for more. Do you perhaps know, or care to speculate, how the higher capacity ones are configured, especially the new 128 GB version?
  • Kristian Vättö - Wednesday, January 30, 2013 - link

    The 128GB model is most likely using new 128Gb (16GB) NAND dies to enable the higher capacity. You can only stack up to eight dies in a single package, so a higher capacity die was needed before you could go over 64GB (8x 16GB is 128GB).

    At least Samsung and IMFT have 128Gb dies in production but they most likely weren't available in volume when the iPad 4 was initially launched, hence the delay.
  • lukarak - Wednesday, January 30, 2013 - link

    Makes sense, thanks for the insight.
  • SAMSAMHA - Wednesday, January 30, 2013 - link

    hi, Anand

    I am curious what board are you using to test this since none of the desktop board with mSATA that I know has SATA 6Gbps interface.
  • SodaAnt - Wednesday, January 30, 2013 - link

    There are msata to sata conversion boards that work fine because msata and sata are electrically the same.
  • Meaker10 - Wednesday, January 30, 2013 - link

    The msi gt60 can ship with a pair of msata gen3 slots configurable in raid.

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