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Old December 8, 2013, 12:04:35 AM
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Default Solid state hybrid drives (SSHD)

Wait a second, what the heck is an SSHD?
SSHD means solid-state hybrid drive, or hybrid disk drive.

Think of SSHDs as regular hard disk drives with integrated non-volatile flash memory areas that acts as a cache for "hot" data, that is, data that is frequently accessed in a non-sequential fashion. Think speed of SSDs for boots and application loads, and capacity (and most of the cost-per-GB) of HDDs.

What do they do for me?
As you use your computer, PlayStation 3, PlayStation 4, or Wii U*, SSHDs cache "hot data" over time. SSHDs only cache data that is random-access in nature, which benefit massively from the near-instant access times from the NAND flash. The NAND flash is sufficiently fast enough in sequential reads to be able to serve highly-random reads, such as boots and application loads, significantly quicker than a normal hard disk drive.

*You'll need to figure a way to power them properly as the Wii U doesn't have enough USB port power by itself on a single USB port connected to a bridge adapter, even on 2.5" drives.

What does that mean for me in the real world?
After a while, your boot times get cut massively, getting very close to SSD boot times. Application load times are also increased in general, and won't have to peg the slow spinning hard disk drive much. You can get more things done in the same time frame and won't have to endure waits.

It won't accelerate things like loading long video files, though, as video files and the like tend to be sequential in nature and very large. (It'll cut down the loading times on your video editing software, though.)

Why is my SSHD churning even though my OS is not reporting any reads, writes, or seeks on the drive?
Your SSHD is performing background caching that is transparent to the OS. All caching is done on the firmware level. This does mean that optimisations are OS and platform-agnostic.

What if I got a power cut on the disk?
Current-generations SSHDs contain capacitors with enough capacitance to flush all uncommitted written data in the DRAM cache and NAND flash to the HDD platters when the drive loses power unexpectedly, unlike some SSDs.

What if the NAND flash area fails?
You will get a normal HDD if the NAND flash area fails for whatever reason; your data is still safe, and you can back up the data before sending it for repairs or replacement.

8 GB doesn't sound like there's a lot of flash memory to play around with.
The NAND flash area caches only random-access data and rapid small writes. This helps to minimize the amount of space used for caching, since long sequential reads and writes are better served by directly hitting the platters. 64 MB of DRAM cache also helps in minimizing writes to the NAND, as it can be used as a buffer before writing to either portion. According to Seagate's own research, about 95% of workloads can be accelerated significantly with only about 2.1 GB of actual data on the NAND flash memory area.

I prefer full control over the NAND flash area.
Western Digital sells the WD Black˛, which is an SSHD capable of displaying as two separate drives within Windows. The SSD portion is 120 GB, while the HDD portion is 1 TB. Be warned that the SSD cannot be reconfigured as a pure cache, the SSD portion is slower than expected in writes, and the HDD portion is inaccessible without the right drivers. You lose all data on the SSD portion if it fails.

I'm a bit concerned about the NAND flash area being MLC flash memory in the latest SSHDs, since they have lower endurance than SLC flash memory. Should I be worried?
It is estimated that with normal use, the HDD portion of the SSHD is more likely to begin to fail than the NAND flash area due to mechanical wear and tear. Due to the limited amount of writes hitting the NAND flash area, the MLC flash memory area should also last a long time even if neither component truly fails.

All writes are written to SLC flash memory areas only, which is also faster compared to writing to MLC flash memory.

I use HDD shock protection software on my hard disk drive in my laptop. Will it stop working?
Toshiba's HDD Protection service is brand-agnostic. It'll stay working even if you switch to a completely different brand's SSHD.
I haven't tested other laptop manufacturers' protection software.

Is a 7200 RPM standard HDD faster than a 5400 RPM SSHD?
Unless you perform frequent long sequential reads/writes (things like file copies, for example), no. Even then, advances in areal density have cancelled out the difference between 7200 and 5400 RPM HDDs in terms of sequential reads and writes.

A 7200 RPM HDD will still be faster than a 5400 RPM SSHD in random access in the event of a cache miss, which is difficult to achieve if the SSHD is used normally, since a cache miss would have to miss these things before hitting the platters:
  • The OS's file cache in RAM
  • Any attached ReadyBoost devices
  • DRAM cache
  • SLC NAND
  • MLC NAND, if exists

Where can I get one?
Seagate, Western Digital, and Toshiba all make single-drive SSHDs. You can purchase these SSHDs from online retail stores and your local computer hardware store. Both desktop (3.5") and laptop (2.5", both full-size (9.5mm) for normal laptops and thin (7mm) for Ultrabooks) variants are available from Seagate.

---

I've actually gotten an SSHD to replace my bog-standard laptop HDD that's starting to be the major bottleneck in my laptop's day-to-day performance. To be exact, I got Seagate's Laptop SSHD. Seeing as it's the full-height variant, it came as a 1 TB 5400 RPM SSHD with 8 GB of MLC flash, and 64 MB of DRAM.

In one fell swoop, I got upgrades in terms of capacity (1000 GB vs. 750 GB), areal density (related to capacity vs. platters), DRAM cache (64 MB vs. 8 MB), and the presence of really fast NAND.

It actually took a while for things to get really going, but after seeing the drive in action, I was left amazed by what it actually did.

I was actually looking at the Windows desktop getting ready in about 15 seconds and the entire thing being "done" by the 37th second. Internet Explorer stopped pegging the hard disk drive. Icons on the desktop and taskbar no longer blank out for a long time. Microsoft Office applications' splash screens flash instead of staying on.

It's like I'm cheating. I think I would probably suggest getting an SSHD to laptop users with a single drive bay. I wasn't a believer when I read benchmarks, but as it turns out, sometimes, benchmarks aren't everything, as owners of SSHDs and Seagate themselves say. What matters is the end-user experience.
  #2  
Old December 8, 2013, 12:46:29 PM
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I'm rather curious on the comparisons between a single1 TB hybrid drive, and a combination of a ~60 GB SSD + 1 TB HDD for an HTPC/media center. HTPCs like mine typically only have a single hard drive bay (two if you sacrifice the floppy bay instead of using a memory card reader), so installing an SSD requires strange installation within the crowded case. A hybrid SSD could work nicely without adding a floating disk.

Then again, I've noticed some HTPC cases (and heck, some standard desktop cases) have been adding a dedicated 2.5" bay next to the 3.5" HDD bay, most likely for the installation of an SSD.
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Old December 9, 2013, 11:50:28 PM
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Quote:
Originally Posted by Cat333Pokémon View Post
I'm rather curious on the comparisons between a single1 TB hybrid drive, and a combination of a ~60 GB SSD + 1 TB HDD for an HTPC/media center. HTPCs like mine typically only have a single hard drive bay (two if you sacrifice the floppy bay instead of using a memory card reader), so installing an SSD requires strange installation within the crowded case. A hybrid SSD could work nicely without adding a floating disk.
If you only need to have fast boot times and application load times, an SSHD is all that you need. Also, there's nothing to manage and/or shuffle between drives, as it's a single drive. (Unless you've opted for WD's "separate" hybrid, that is...)

Quote:
Originally Posted by Cat333Pokémon View Post
Then again, I've noticed some HTPC cases (and heck, some standard desktop cases) have been adding a dedicated 2.5" bay next to the 3.5" HDD bay, most likely for the installation of an SSD.
Perhaps.

Or maybe they'll remove the 3.5" bays entirely someday.

Last edited by Twiggy; December 9, 2013 at 11:52:58 PM.
 
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