The Intel SSD 520

Intel sent us a 240GB and 60GB SSD 520 for review, but the performance specs of the entire family are in the table below:

The Intel SSD 520 is available in both 9.5mm and 7mm versions, with the exception of the 480GB flavor that only comes in a 9.5mm chassis. The 520's uses Intel's standard 7mm chassis with a 2.5mm removable plastic adapter that we've seen since the X25-M G2. The plastic adapter allows the drive to fit in bays designed for 9.5mm drives. Note that Intel doesn't ship shorter screws with the 9.5mm drives so you can't just remove the plastic adapter and re-use the existing screws if your system only accepts a 7mm drive.

Inside the drive we see the oh-so-familiar SandForce SF-2281 controller and Intel 25nm MLC NAND. The controller revision appears unchanged from other SF drives we've seen over the past year. The PCB design is unique to the 520, making it and the custom Intel firmware the two noticeable differences between this and other SF-2281 drives.


Intel uses the metal drive chassis as a heatsink for the SF-2281 controller

The SF-2281 Controller

I've explained how the SF-2281 works in the past, but for those of you who aren't familiar with the technology I'll provide a quick recap. Tracking the location of data written to an SSD ends up being one of the most difficult things a controller has to do. There are a number of requirements that must be met. Data can't be written to the same NAND cells too frequently and it should be spread out across as many different NAND die as possible (to improve performance). For large sequential transfers, meeting these (and other) requirements isn't difficult. Problems arise when you've got short bursts of random data that can't be combined. The end result is leaving the drive in a highly fragmented state that is suboptimal for achieving good performance.

You can get around the issue of tracking tons of data by simply not allowing small groups of data to be written. Track data at the block level, always requiring large writes, and your controller has a much easier job. Unfortunately block mapping results in very poor small file random write performance as we've seen in earlier architectures so this approach isn't very useful for anything outside of CF/SD cards for use in cameras.

A controller can rise to the challenge by having large amounts of cache (on-die and externally) to help deal with managing huge NAND mapping tables. Combine tons of fast storage with a fast controller and intelligent firmware and you've got a good chance of building a high performance SSD.

SandForce's solution leverages the work smart not hard philosophy. SF controllers reduce the amount of data that has to be tracked on NAND by compressing any data the host asks to write to the drive. From the host's perspective, the drive wrote everything that was asked of it, but from the SSD's perspective only the simplest representation of the data is stored on the drive. Running real-time compression/de-duplication algorithms in hardware isn't very difficult and the result is great performance for a majority of workloads (you can't really write faster than a controller that doesn't actually write all of the data to NAND). The only limit to SandForce's technology is that any data that can't be compressed (highly random bits or data that's already compressed) isn't written nearly as quickly.

Intel does a great job of spelling out the differences in performance depending on the type of data you write to the SSD 520, but it's something that customers of previous Intel SSDs haven't had to worry about. Most client users stand to benefit from SandForce's technology and it's actually very exciting for a lot of enterprise workloads as well, but you do need to pay attention to what you're going to be doing with the drive before deciding on it.

The Intel SSD Toolbox

The Intel SSD 520 works flawlessly with the latest version of Intel's SSD Toolbox. The toolbox allows you to secure erase the drive from within Windows, and it also allows you to perform firmware updates and pull SMART info from the drive. Unlike other SandForce toolboxes, Intel's software works fine with Intel's RST drivers installed.

The Test

CPU

Intel Core i7 2600K running at 3.4GHz (Turbo & EIST Disabled) - for AT SB 2011, AS SSD & ATTO

Motherboard:

Intel DH67BL Motherboard

Chipset:

Intel H67

Chipset Drivers:

Intel 9.1.1.1015 + Intel RST 10.2

Memory: Corsair Vengeance DDR3-1333 2 x 2GB (7-7-7-20)
Video Card: eVGA GeForce GTX 285
Video Drivers: NVIDIA ForceWare 190.38 64-bit
Desktop Resolution: 1920 x 1200
OS: Windows 7 x64
Introduction Random & Sequential Read/Write Speed
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  • GrizzledYoungMan - Monday, February 06, 2012 - link

    Excellent review, Anand. I really appreciate your focus on reliability/compatibility over performance in your latest SSD reviews; that really reflects my own experience in terms of where SSDs need to improve.

    Do you (or anyone) know when the Intel 520 is scheduled to be available for sale? I didn't notice this information in your article.

    Here's hoping it's soon. I am returning a newly purchased Crucial m4 (which has a number of rather absurd semi-known/unacknowledged issues, like stuttering with Intel RST drivers installed, and failing to wake up from sleep) and seeking to replace it with an Intel drive. After owning OCZ and Crucial, I am really looking forward to not having to extensively modify my system just to get things working.
    Reply
  • GrizzledYoungMan - Monday, February 06, 2012 - link

    This just came up on Amazon: http://www.amazon.com/Intel-SSDSC2CW120A3K5-2-5-In...

    Price looks right, and is sold by Amazon directly. Can anyone confirm that this model number is correct?
    Reply
  • ckryan - Monday, February 06, 2012 - link

    Cherryville has been selling in small quantities for weeks now. Benches and pics have been out there. I thoroughly enjoy every one of Anand's SSD reviews as it's never just a review of the drive, but in this case the 520's performance profile has been established well in advance of NDA expiration.

    Intel's reliability is well deserved IMHO. For those of us wishing against hope for Intel's 10 channel 6gbps controller, keep hoping. As late as 60 days ago, I was hoping that the 520 would utilize the Marvell controller, but when Cherryville started shipping a few weeks back, all hope was lost. And it was pretty obvious when the specs were leaked months and months ago.

    Intel's own controller is not fast by the standards of today, but Intel really got to the heart of the matter with the first and second gen drives, which is speed is superfluous without reliability.

    SandForce drives have been tamed to a large extent with the 3.3.2FW, but I'm unconvinced of their long term reliability -- the nDurance chart literature reproduced in the article is not realistic in any way, and in my experience SF drives tend to lose in endurance compared to it's competitors. I still own and use SF drives, but when I need reliability over speed, SF is not the way I personally choose to go.

    I respect Intel's decision to go SF, and in it's entirely likely that no drive has received the internal scrutiny that the 520 has -- and I'm sure it will pay dividends. But I won't be selling my older Intel drives on eBay anytime soon.
    Reply
  • GrizzledYoungMan - Monday, February 06, 2012 - link

    Good comment, and useful thoughts, thank you.

    Since you seem to have a lot of experience with these devices, and similar priorities as me, which would you pick for the system disk of a workstation: the 320 or the 520, both at 120GB? I'm on a p55 mobo with a 3gb/s SATA controller, FYI.

    While the performance of the 520 series is attractive, I'm still inclined to believe that I wouldn't notice the real world difference between the two. In which case the 320 series wins on demonstrated reliability.
    Reply
  • ckryan - Monday, February 06, 2012 - link

    The 320 has a great record -- it's one reliability fault was the rare 8MB error, since corrected. Firmware is so crucial with SSDs, and the actual act of updating FW can cause issues of it's own (ala the Samsung 830, another excellent drive).

    On a 3gbps Intel mobo port you won't get the sequential speeds, but you will get the good random performance and the 520 handily bests it's fore-bearers in that area.

    So I suppose that the issue of price should be considered. The 120GB 320 and 520 are going to be nearly the same price -- so you'd be getting more with the 520. I would say if you're comfortable with it, get the 520.

    Regardless of whether SSD or HDD, you should be in a position that if the drive dies 20 minutes from now, restoring your data to it shouldn't be a problem. With that in mind, you can probably bet that the 520 will hold out for it's 5 year warranty. If it doesn't, you still have a 5 year warranty.

    As an aside, I recently bought a 320 series 120GB just to have on hand should the need arise, and it is pretty magnificent. I think most people would be just as happy with a 320 than a faster 520 -- the people who crave speed are going to get the fastest drive anyway, so for everybody else the 320 series is still a viable option.
    Reply
  • Roland00Address - Monday, February 06, 2012 - link

    The 80gb intel 320 has routinely been on sale for the last month from several different online retailers. The sales involve mail in rebates but you see final MIR prices being between 70 to 90 dollars for the 80gb.

    The 120gb intel 320 on the other hand hasn't really gone on sale in Janurary, only time it went on sale in the last few months was a black friday sale (and BF is not a normal thing.)
    Reply
  • GrizzledYoungMan - Tuesday, February 07, 2012 - link

    Just bought a 120gb Intel 320 series SSD for $182.00 - nearly $1.50 a gig. Not bad.

    Between the reliability (both in terms of software, architecture, and power loss protection) and the insane IO performance on reads at lower queue depths, I feel confident I made the right choice.
    Reply
  • alpha754293 - Monday, February 06, 2012 - link

    Reading this, I'm tempted to buy the 180 GB version because I will be using it in a HPC environment.

    And if the OCZ Vertex 3 is going to have BSOD issues, I'd rather pay a little bit of a premium or lose a little in storage capacity in order to make sure that the system will be humming along perfectly/nicely.

    Such a shame/waste that the Vertex 3s are relegated to being just data drives.
    Reply
  • neotiger - Monday, February 06, 2012 - link

    It doesn't look like Intel 520 has any capacitors to prevent data loss.

    So how is this SSD any different from the 5,000 other SandForce SSD's already in the market, except this one is much more expensive than the others?
    Reply
  • Sunrise089 - Monday, February 06, 2012 - link

    Read the article ;) Reply

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