It's called the Intel SSD 320, but the part number should give away just what we're looking at here:

This is the long awaited third generation Intel based SSD. This is the G3. And at this point it's around 6 months late.

Back then it was simply called the Postville Refresh on Intel's roadmaps (Postville was the 34nm Intel X25-M G2). It would use 25nm Intel NAND, feature improved performance and full disk encryption - all behind a 3Gbps SATA interface.

When I spoke with Intel about the drive last year, all indications pointed to it being faster than drives based on SandForce's SF-1200 controller. And it is:

Intel SSD 320 300GB vs. Corsair Force F120
  AT Storage Bench 2011 (Heavy) AT Storage Bench 2011 (Light)
Corsair Force F120 120.1 MB/s 155.9 MB/s
Intel SSD 320 300GB 132.8 MB/s 161.7 MB/s

Without turning to any real time compression/deduplication techniques, Intel has built a drive that's faster than the SF-1200. You also get that famed Intel SSD reliability:

There's just one issue. The SF-1200 was the king of 2010. This year is shaping up to be all about the SF-2200 and the G3 isn't quite as competitive there. Intel realized this as well and thus we got the Intel SSD 510 to address the high performance market. Intel claims the 510 should have the same failure rate as the 34nm X25-M G2 at ~0.6% per year.

The Intel SSD 320 by comparison is aimed at the mainstream market. Remember that's what the M in X25-M always stood for to begin with. As a result we get lower pricing:

Intel SSD Comparison
  X25-M G2 160GB Intel SSD 320 40GB Intel SSD 320 80GB Intel SSD 320 120GB Intel SSD 320 160GB Intel SSD 320 300GB Intel SSD 320 600GB SSD 510 120GB SSD 510 250GB
User Capacity 149GB 37GB 74GB 111GB 149GB 279GB 558GB 111GB 232GB
Random Read Performance Up to 35K IOPS Up to 30K IOPS Up to 38K IOPS Up to 38K IOPS Up to 39K IOPS Up to 39.5K IOPS Up to 39.5K IOPS Up to 20K IOPS Up to 20K IOPS
Random Write Performance Up to 8.6K IOPS Up to 3.7K IOPS Up to 10K IOPS Up to 14K IOPS Up to 21K IOPS Up to 23K IOPS Up to 23K IOPS Up to 8K IOPS Up to 8K IOPS
Sequential Read Performance Up to 250MB/s Up to 200MB/s Up to 270MB/s Up to 400MB/s (6Gbps) Up to 500MB/s (6Gbps)
Sequential Write Performance Up to 100MB/s Up to 45MB/s Up to 90MB/s Up to 130MB/s Up to 165MB/s Up to 205MB/s Up to 220MB/s Up to 210MB/s (6Gbps) Up to 315MB/s (6Gbps)
Price $404 $89 $159 $209 $289 $529 $1069 $284 $584

It's still early in the 25nm ramp, but the 25nm Intel SSD 320 is cheaper than the 34nm Intel SSD 510. The only issue is that OCZ is very competitive with its pricing as well and compared to the Vertex 2, Intel's SSD 320 isn't really any cheaper. Intel likes to maintain its 65% profit margins so even though it makes the NAND and the controller in the 320, we're unlikely to see these drives drop below competitive pricing.

Intel expects the 25nm SSD 320 to be even more reliable than the 510 or X25-M.

The Same Controller

The Intel SSD 320, like the 310 and X25-M before it, uses an Intel branded controller. Opening up the 320 reveals a near identical controller to what we saw in the 34nm X25-M G2 housing:

You'll notice the part number is identical to 2009's X25-M G2 controller. In fact, it's the same controller. Apparently the G2 controller had a number of features on-die, but not implemented in firmware. Things like full disk encryption and NAND redundancy never made it out in G2 but are here in the 320 all thanks to new firmware. And no, G2 owners aren't getting it.


Intel's X25-M G1 Controller


Intel's X25-M G2 Controller


Intel's SSD 320 Controller

Since the controller hasn't changed, the basic architecture of the SSD hasn't changed either. Intel still doesn't store any user data in its external DRAM cache and there's still a 256KB on-die SRAM.


64MB 166MHz SDRAM

Next to the Intel controller is a 64MB 166MHz SDRAM device, now made by Hynix. You'll notice that the DRAM chip is a lot smaller than what we've seen in previous X25-M generations, despite growing in capacity. Intel actually turned to mobile SDRAM for use in the SSD 320 to help save on power. While the X25-M G1 and G2 both used a conventional 3.3V SDRAM device, Intel moved to a 1.8V mobile SDRAM chip with the 320.


Intel X25-M G1: 16MB 166MHz SDRAM


Intel X25-M G2: 32MB 133MHz SDRAM

Intel always prided itself on not storing any user data in its DRAM cache. The external DRAM is only used to cache mapping tables and serve as the controller's scratchpad. In the event of a sudden loss of power, Intel only has to commit whatever data it has in its SRAM to NAND. To minimize the amount of data loss in the event of a sudden power failure, Intel outfitted the SSD 320 with an array of six 470µF capacitors in parallel.

We've seen large capacitors on SSDs before, primarily the enterprise SandForce drives that boast a 0.09F supercap. Intel claims that for its design a single large capacitor isn't necessary given the minimal amount of data that's cached. It further claims that an array of multiple capacitors in parallel allows for much better reliability - if one capacitor fails the array is still useful (vs. a single point of failure in the case of the supercap).

Spare Area, 3Gbps Only, AES-128
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  • etamin - Monday, March 28, 2011 - link

    This is probably a noob question for many of you but can someone explain to me why having a 6gbps controller/interface would increase performance if the drive itself maxes out at 240MB/s sequential read speed (128KB)? isn't 3gbps equal to 384MB/s? If the Intel 320 cannot saturate the SATA 3gbps bandwidth, what good would a 6gpbs bandwidth do for it? similarly, why do a lot of disk drives today have 6gbps interfaces when they can barely saturate 1/3 of a 3gbps interface? Thanks. Reply
  • nonzenze - Monday, March 28, 2011 - link

    Because the controller can burst higher if data is handy in a cache. Reply
  • etamin - Tuesday, March 29, 2011 - link

    I see. Is there a measure for burst speeds and I'm assuming this only applies to read operations? Reply
  • UNHchabo - Monday, March 28, 2011 - link

    SATA uses 8b/10b encoding in all current revisions. This means that the theoretical limit for SATA 3Gb/s is 300MB/s. Reply
  • etamin - Tuesday, March 29, 2011 - link

    very interesting, I'll be sure to keep that possibility in mind before converting other standards next time. Reply
  • Chloiber - Tuesday, March 29, 2011 - link

    As you can clearly see with SATA3 SSDs running at SATA2, it's way lower. Reply
  • etamin - Thursday, March 31, 2011 - link

    yes, that is obvious. I asked because I want to understand the architectural reason behind it. Reply
  • Nentor - Monday, March 28, 2011 - link

    They are all so close to each other an unscrupulous HD manufacturer could use them to show there is barely any difference between a SSD and a HD.

    Why add keep adding them to the SSD articles?
    Reply
  • etamin - Monday, March 28, 2011 - link

    I think having HDDs in these articles sets a good baseline for those of us who don't already own ssds. Personally I'd actually like to see more hdds like 5400rpm notebook drives since many of these SSDs will be going into notebooks. Reply
  • wvh - Monday, March 28, 2011 - link

    What exactly do I need to have encryption support? I've never noticed a SATA password option in my BIOS. Do most laptops support this?

    Lackluster as the performance seems to be, encryption support and increased reliability – while not sexy – are important, too. If not the enthusiast market, the corporate world might have more interest in such drives.
    Reply

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