A Short Guide To SSD

Discussion in 'Hardware' started by Digital Doctor, Mar 1, 2011.

Share This Page

  1. Digital Doctor

    Digital Doctor Loving AMD's new AM1 CPU

    Joined:
    Dec 6, 2009
    Messages:
    1,903
    Likes Received:
    0
    The facts about solid state hard disks:

    Note: Windows 7 will disable disk defragmentation on SSD system drives.

    Because SSDs perform extremely well on random read operations, defragmenting files isn’t helpful enough to warrant the added disk writing defragmentation produces. The FAQ section below has some additional details.

    By default, Windows 7 will disable Superfetch, ReadyBoost, as well as boot and application launch prefetching on SSDs with good random read, random write and flush performance. These technologies were all designed to improve performance on traditional HDDs, where random read performance could easily be a major bottleneck.
    See the FAQ section for more details.

    Since SSDs tend to perform at their best when the operating system’s partitions are created with the SSD’s alignment needs in mind, all of the partition-creating tools in Windows 7 place newly created partitions with the appropriate alignment.

    * * * * * Frequently Asked Questions * * * * *

    Does Windows 7 fully support software trim?

    Yes.

    Does Windows XP fully support software trim?

    No, but there are alternatives, intel toolbox and the crucial wiper tool for example.

    Intel SSD toolbox for XP

    Crucial wiper tool for XP

    Does Ubuntu fully support software trim?

    Yes, from version 10.10

    Will disk defragmentation be disabled by default on SSDs?

    Yes. The automatic scheduling of defragmentation will exclude partitions on devices that declare themselves as SSDs. Additionally, if the system disk has random read performance characteristics above the threshold of 8 MB/sec, then it too will be excluded. The threshold was determined by internal analysis.

    The random read threshold test was added to the final product to address the fact that few SSDs on the market today properly identify themselves as SSDs. 8 MB/sec is a relatively conservative rate. While none of our tested HDDs could approach 8 MB/sec, all of our tested SSDs exceeded that threshold. SSD performance ranged between 11 MB/sec and 130 MB/sec. Of the 182 HDDs tested, only 6 configurations managed to exceed 2 MB/sec on our random read test. The other 176 ranged between 0.8 MB/sec and 1.6 MB/sec.


    Will Superfetch be disabled on SSDs?

    Yes, for most systems with SSDs.

    If the system disk is an SSD, and the SSD performs adequately on random reads and doesn’t have glaring performance issues with random writes or flushes, then Superfetch, boot prefetching, application launch prefetching, ReadyBoost and ReadDrive will all be disabled.

    First generation SSDs have severe enough random write and flush problems that ultimately lead to disk reads being blocked for long periods of time. With Superfetch and other prefetching re-enabled, performance on key scenarios is markedly improved.

    Is NTFS Compression of Files and Directories recommended on SSDs?

    Compressing files help save space, but the effort of compressing and decompressing requires extra CPU cycles and therefore power on mobile systems. That said, for infrequently modified directories and files, compression is a fine way to conserve valuable SSD space and can be a good tradeoff if space is truly a premium.

    It's not recommended to compress files or directories that will be written to with great frequency. Your Documents directory and files are likely to be fine, but temporary internet directories or mail folder directories aren’t such a good idea because they get large number of file writes in bursts.


    Does the Windows Search Indexer operate differently on SSDs?

    No.

    Is Bitlocker’s encryption process optimized to work on SSDs?

    Yes, on NTFS. When Bitlocker is first configured on a partition, the entire partition is read, encrypted and written back out. As this is done, the NTFS file system will issue Trim commands to help the SSD optimize its behavior.

    For users concerned about their data privacy and protection enabling Bitlocker on their drives is a wise choice.


    Does Media Center do anything special when configured on SSDs?

    No. While SSDs do have advantages over traditional HDDs, SSDs are more costly per GB than their HDD counterparts. For most users, a HDD optimized for media recording is a better choice, as media recording and playback workloads are largely sequential in nature.

    Does Write Caching make sense on SSDs and does Windows 7 do anything special if an SSD supports write caching?

    Some SSD manufacturers including RAM in their devices for more than just their control logic; they are mimicking the behavior of traditional disks by caching writes, and possibly reads. For devices that do cache writes in volatile memory, Windows 7 expects flush commands and write-ordering to be preserved to at least the same degree as traditional rotating disks. Additionally, Windows 7 expects user settings that disable write caching to be honored by write caching SSDs just as they are on traditional disks.

    Do RAID configurations make sense with SSDs?

    Yes. The reliability and performance benefits one can obtain via HDD RAID configurations can be had with SSD RAID configurations.

    Should the pagefile be placed on SSDs?

    Yes. Most pagefile operations are small random reads or larger sequential writes, both of which are types of operations that SSDs handle well.

    In looking at telemetry data from thousands of traces and focusing on pagefile reads and writes, peolple find that:

    •Pagefile.sys reads outnumber pagefile.sys writes by about 40 to 1,
    •Pagefile.sys read sizes are typically quite small, with 67% less than or equal to 4 KB, and 88% less than 16 KB.
    •Pagefile.sys writes are relatively large, with 62% greater than or equal to 128 KB and 45% being exactly 1 MB in size.
    In fact, given typical pagefile reference patterns and the favorable performance characteristics SSDs have on those patterns, there are few files better than the pagefile to place on an SSD.

    Are there any concerns regarding the Hibernate file and SSDs?

    No, hiberfile.sys is written to and read from sequentially and in large chunks, and thus can be placed on either HDDs or SSDs.

    Do SSD drives require cooling?

    No, They are designed to be used in high end laptops where no drive cooling is present. If you are putting them in a high end pc case like a lian li for example, it makes more sense to remove the hard drive cage and in it's place put in a watercooling radiator, that way the front intake fan will be pushing cold air straight on to it.

    How long do SSD drives last?

    Over 100 years if maintained properly.

    Are SSD drives fragile?

    No, not only do they have five times greater shock resistance, of course they have no internal moving parts to damage.

    Does TRIM work in IDE mode?

    Yes, TRIM works in IDE mode but most people rather run in AHCI as it's more convenient to secure erase your drive, this cannot be performed in IDE mode.

    Is 300MB/s the limit for SSD drives on a SATA 2 controller?

    Yes for a single drive no for RAID 0, it works on an additive principle, the more drives in a RAID 0 array the faster they will perform.

    Which controller will perform best with an SSD?

    Onboard SATA II will outperform PCI slot RAID solutions and by a big margin, PCI raid is limited to the throughput of the PCI slot, which is much more limited than a motherboards SATA II direct to chipset connection. It's actually PCI that's the fake raid.

    How can i check if TRIM is enabled?

    Run command prompt as an administrator then enter this:

    Command prompt > fsutil behavior query disabledeletenotify

    DisableDeleteNotify = 1 (Windows TRIM commands are disabled)
    DisableDeleteNotify = 0 (Windows TRIM commands are enabled)

    Windows should automatically enable TRIM but it's a good idea to check.


    I'm running my drive in IDE mode what about NCQ?

    Don't worry, NCQ only really benefits high end work stations, it only really helps for servers processing multiple requests from different users at once. Some say they get slightly higher performance by switching this function off.

    I want to compress my SSD to save space is this wise?

    Yes! in most cases the drive will perform faster.
     
  2. phil2715

    phil2715 Registered + Sale

    Joined:
    Jun 4, 2004
    Messages:
    882
    Likes Received:
    0
    They make sense in some circumstances, but I would have thought for the vast majority of home users, the requirement for SSD RAID is much lower than mechanical HDD RAID as you lose out on TRIM support.

    Also, isn't this just copypasta from another forum? (e.g. Tom's)

    Not quoting source = mighty rude IMHO.
     
  3. Digital Doctor

    Digital Doctor Loving AMD's new AM1 CPU

    Joined:
    Dec 6, 2009
    Messages:
    1,903
    Likes Received:
    0
    Just snippets of info from different sites and bits i added i thought id bundle together.

    Seeing as most ssd drives have a lifespan of over 140 years raid shouldnt be a problem, if you think about it youre taking stress off using a single drive in raid0 as the data is equally spread across the drives. I think trim is a software driver issue with intel isnt it?

    I know trim goes into more depth than that and does more but im sure it will get sorted in the end if intel get their act together.
     
  4. Thourot

    Thourot New Member

    Joined:
    Nov 2, 2010
    Messages:
    19
    Likes Received:
    0
    i am not really knowledgeable when it comes to pc but i love reading forums, you guys are genius and thanks i was able to learn here..
     
  5. jacobzcoool

    jacobzcoool Chav Hunter

    Joined:
    Oct 15, 2005
    Messages:
    5,447
    Likes Received:
    0
    It depends on the controller. A good RAID card might have TRIM support now, and software RAID in the OS will as it sees the drives as SSDs, but a mobo RAID chipset still probably won't.
     
  6. phil2715

    phil2715 Registered + Sale

    Joined:
    Jun 4, 2004
    Messages:
    882
    Likes Received:
    0
    Really? It was my understanding that RAID controllers could not pass the TRIM command through to the SSDs and this was a more of a fundamental technology issue.

    As far as TRIM goes, your RAID array would fly to start with but without TRIM, as you continue to use it, performance would degrade massively until you need to secure (?) erase the whole array and start again.

    Personally (especially given the performance of the new Vertex 3), I'd rather stick to a single drive with good TRIM implementation.
     
  7. Ninjagordy

    Ninjagordy Winner of The Game (UJFL)

    Joined:
    Jul 22, 2004
    Messages:
    1,359
    Likes Received:
    0
    as far as raid 0 is concerned. i have 2 Kingston Vnow 64gb ssd's in raid 0. hdd tach has just given me an average read speed of 505.8mb/s And write speeds of 240.6MB/S

    now , how accurate that is im not sure , thats the rig in my sig for anyone wondering so raid 0 with ssd's is for sure waaaay faster than raid 0 on conventional platter drives.

    cheers

    Gordy!
     
  8. phil2715

    phil2715 Registered + Sale

    Joined:
    Jun 4, 2004
    Messages:
    882
    Likes Received:
    0
    Pass me the humble pie. Some lunchtime googling tells me that at the very least Intel was offering TRIM over RAID on selected motherboards nearly 12 months ago. How time flies ;)

    That said, I would want to be certain the drives could use TRIM over RAID before comitting, as un-TRIMed performance can be fairly terrible:

    http://www.anandtech.com/show/4202/the-intel-ssd-510-review/13

    (slightly OT, but I'm pretty disappointed in the SSD510's performance. My G2 is brilliant and class leading at launch. Intel have really dropped the ball IMHO.)
     
  9. Koolpc

    Koolpc Not From Earth

    Joined:
    Nov 19, 2002
    Messages:
    1,940
    Likes Received:
    0
    Nice thread!
     
  10. Digital Doctor

    Digital Doctor Loving AMD's new AM1 CPU

    Joined:
    Dec 6, 2009
    Messages:
    1,903
    Likes Received:
    0
    Forthy youre a diamond, you have another worshipper...
     
  11. Koolpc

    Koolpc Not From Earth

    Joined:
    Nov 19, 2002
    Messages:
    1,940
    Likes Received:
    0
    Thing with Forthy is that he keeps running but doesn't get anywhere!! lol
     
  12. Kermit98

    Kermit98 Regular Kustomer

    Joined:
    Apr 16, 2008
    Messages:
    194
    Likes Received:
    0
    From what I have read (if someone knows better please correct), at the moment you can use Trim on Trim enabled drives on a Intel RAID controler as long as it not part of a RAID array.

    There was some confusion as intel's help file with the driver update said it would support in a RAID array as well but that has since been corrected. Although it does make you think that it will be coming soon.

    Adaptec and Areca are also expected to release TRIM supporting cards before too long.

    I wont switch to SSD until the trim issue is sorted, its not the performance of multiple SSDs I am aiming for with RAID (altough a great benefit). But sans TRIM the performance we degrade rather quickly.
    Main reason I want RAID SSDs is volume, for over 500GB you are talking stupid amounts of money. Some of the smaller drives have started coming into semi-reasonable price ranges.
     
  13. Digital Doctor

    Digital Doctor Loving AMD's new AM1 CPU

    Joined:
    Dec 6, 2009
    Messages:
    1,903
    Likes Received:
    0
    Intel have released drives that support trim on raid0 but not raid5
     
  14. Kermit98

    Kermit98 Regular Kustomer

    Joined:
    Apr 16, 2008
    Messages:
    194
    Likes Received:
    0
    Someone should tell the nice people at intel to update their website then

    http://www.intel.com/support/chipsets/imsm/sb/CS-031491.htm