The Intel SSD 320 Review: 25nm G3 is Finally Here
by Anand Lal Shimpi on March 28, 2011 11:08 AM EST- Posted in
- IT Computing
- Storage
- SSDs
- Intel
- Intel SSD 320
Spare Area and Redundant NAND
Intel's controller is a 10-channel architecture and thus drive capacities are still a little wonky compared to the competition. Thanks to 25nm NAND we now have some larger capacities to talk about: 300GB and 600GB.
Intel sent a 300GB version of the 320 for us to take a look at. Internally the drive has 20 physical NAND devices. Each NAND device is 16GB in size and features two 64Gbit 25nm 2-bit MLC NAND die. That works out to be 320GB of NAND for a drive whose rated capacity is 300GB. In Windows you'll see ~279GB of free space, which leaves 12.8% of the total NAND capacity as spare area.
Around half of that spare area is used to keep write amplification low and for wear leveling, both typical uses of spare area. The other half is for surplus NAND arrays, a RAID-like redundancy that Intel is introducing with the SSD 320.
As SandForce realized in the development of its controller, smaller geometry NAND is more prone to failure. We've seen this with the hefty reduction in rated program/erase cycles since the introduction of 50nm NAND. As a result, wear leveling algorithms are very important. With higher densities however comes the risk of huge amounts of data loss should there be a failure in a single NAND die. SandForce combats the problem by striping parity data across all of the NAND in the SSD array, allowing the recovery of up to a full NAND die should a failure take place. Intel's surplus NAND arrays work in a similar manner.
Instead of striping parity data across all NAND devices in the drive, Intel creates a RAID-4 style system. Parity bits for each write are generated and stored in the remaining half of the spare area in the SSD 320's NAND array. There's more than a full NAND die (~20GB on the 300GB drive) worth of parity data on the 320 so it can actually deal with a failure of more than a single 64Gbit (8GB) die.
Sequential Write Cap Gone, but no 6Gbps
The one thing that plagued Intel's X25-M was its limited sequential write performance. While we could make an exception for the G1, near the end of the G2's reign as most-recommended-drive the 100MB/s max sequential write speed started being a burden(especially as competing drives caught up and surpassed its random performance). The 320 fixes that by increasing rated sequential write speed to as high as 220MB/s.
You may remember that with the move to 25nm Intel also increased page size from 4KB to 8KB. On the 320, Intel gives credit to the 8KB page size as a big part of what helped it overcome its sequential write speed limitations. With twice as much data coming in per page read it's possible to have a fully page based mapping system and still increase sequential throughput.
Given that the controller hasn't changed since 2009, the 320 doesn't support 6Gbps SATA. We'll see this limitation manifest itself as a significantly reduced sequential read/write speed in the benchmark section later.
AES-128 Encryption
SandForce introduced full disk encryption starting in 2010 with its SF-1200/SF-1500 controllers. On SandForce drives all data written to NAND is stored in an encrypted form. This encryption only protects you if someone manages to desolder the NAND from your SSD and probes it directly. If you want your drive to remain for your eyes only you'll need to set an ATA password, which on PCs is forced by setting a BIOS password. Do this on a SandForce drive and try to move it to another machine and you'll be faced with an unreadable drive. Your data is already encrypted at line speed and it's only accessible via the ATA password you set.
Intel's SSD 320 enables a similar encryption engine. By default all writes the controller commits to NAND are encrypted using AES-128. The encryption process happens in realtime and doesn't pose a bottleneck to the SSD's performance.
The 320 ships with a 128-bit AES key from the factory, however a new key is randomly generated every time you secure erase the drive. To further secure the drive the BIOS/ATA password method I described above works as well.
A side effect of having all data encrypted on the NAND is that secure erases happen much quicker. You can secure erase a SF drive in under 3 seconds as the controller just throws away the encryption key and generates a new one. Intel's SSD 320 takes a bit longer but it's still very quick at roughly 30 seconds to complete a secure erase on a 300GB drive. Intel is likely also just deleting the encryption key and generating a new one. Without the encryption key, the data stored in the NAND array is meaningless.
The Test
| CPU |
Intel Core i7 965 running at 3.2GHz (Turbo & EIST Disabled) Intel Core i7 2600K running at 3.4GHz (Turbo & EIST Disabled) - for AT SB 2011, AS SSD & ATTO |
| Motherboard: |
Intel DX58SO (Intel X58) Intel H67 Motherboard |
| Chipset: |
Intel X58 + Marvell SATA 6Gbps PCIe Intel H67 |
| Chipset Drivers: |
Intel 9.1.1.1015 + Intel IMSM 8.9 Intel 9.1.1.1015 + Intel RST 10.2 |
| Memory: | Qimonda DDR3-1333 4 x 1GB (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 |
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y.a.k - Tuesday, March 29, 2011 - link
Don't forget about notebooks...pvdw - Tuesday, March 29, 2011 - link
Thanks for all the good info and thorough reviews. One of the areas I'm particularly interested in is the performance of an SSD when hosting a Virtual Machine. The reason is that I run Windows Vista (soon to be 7) as a host OS and then XP or Linux for various work stuff in VMs. Any chance of adding some sample VM booting + app loading to the mix?I'm thinking that virtual disks are probably quite random data and so would favour non-SF drives, but I'm not really sure.
NCM - Wednesday, March 30, 2011 - link
I've timed boot and app launches from otherwise identical systems on both SSD and a conventional hard drive on the same workstation (OS X on a current model MacPro workstation). The improvement is by a factor of 3-4. Although we do have a couple of VM setups they're not on the SSD machine, but I'd hope for the speed increase to be in the same range—lots and lots of little files to be read.GoGoGoGo - Wednesday, March 30, 2011 - link
...but not fantastic eitherFor those of us planning to put an SSD in a current laptop (which pretty much makes 6Gbps performace irrelevant) this seems to be an okay option, although not as groundbreaking as the original X-25 a while back.
I do wish more 3Gbps numbers where included for the Vertex3 since for a lot of us that´s what going to matter anyhow. Also, is there a difference in power usage for the Vertex3 when hooked up to a 3Gbps controller or not?
TheSwede86 - Wednesday, March 30, 2011 - link
Hi!Have a friend in the US (Miami) and I am wondering where I can buy this in the US?
The pressrelease said "Best Buy" but on Best Buy's homepage I can't find it.
Anyone seen it "in the wild" and if so where?
Thanks!
Cowbell - Thursday, March 31, 2011 - link
Many new SSDs got built in encryption like the SF series, but the real question I'd love to see more details on Anand, is if the encryption is linked to the ATA password, or perhaps some other software like OCZ's toolbox, but that again is only available on the PRO drives and leaves consumer drives out in the cold. If not then the encryption is only good for fast wipe, nothing else.In addition, I'd love some tests on just how resistant SSD's are to brute forcing the ATA password on non encrypted drives, for instance OCZs SSDs need a power cycle on each 5th attempt to unlock, and how easy it is to read the ATA password in plaintext from the maintenance area of the disk.
To top it all of I'd also love some tests on how easy it is to dump data from SSD flash cells/modules if an attacker were to obtain the disk and disassemble it.
4EverLearning - Monday, May 9, 2011 - link
I second this request. There is much confusion about this topic: what is required to enable encryption, and whether or not it is virtually infallible or a joke.As always, thanks Anand -- great stuff.
paulzeb - Saturday, April 2, 2011 - link
Anand,First, Congratulations for another job well done !
I am a Mac OSX user with MacPro, and I have Just one question:
I read in the review "The Intel SSD 320 Review: 25nm G3 is Finally Here":
"" A side effect of having all data encrypted on the NAND is that secure erases happen much quicker. You can secure erase a SF drive in under 3 seconds as the controller just throws away the encryption key and generates a new one. Intel's SSD 320 takes a bit longer but it's still very quick at roughly 30 seconds to complete a secure erase on a 300GB drive. ""
My experience with Secure erase and Disk Utility on an OCZ Vertex2 is that it take many many minutes depending on the SSD size. Same with a Secure erase and Disk Utility on the Intel X25 G2 Postville.
Will it take only 30 seconds on the new Intel G3 Postville Refresh ???
Thanks for your answer,
Paul
noblemo - Wednesday, April 6, 2011 - link
If I recall correctly, a previous article recommended formatting SSDs with 10-30% of spare area set aside to improve performance. Does this recommendation still apply to the G3?If an extra 20% is under-allocated (for a total of 26.25% on the G3), then the user-available area would be about 220GiB for a 320GB drive, and 110GiB for a 160GB drive.
Omid.M - Wednesday, April 20, 2011 - link
Anand,Can you please comment on this? I recall this recommendation as well.
Does it still hold true? So, if I buy the Vertex 3 or Intel 320 and drop it into my MBP, should I format the drive to have 10-15% area unused (spare) and will that make a significant difference in performance, compared to having 0% spare area (i.e. using SSD as-is, no formatting) ?