Important SSD notes: In Linux, the operating system keeps both HDD’s and SSD’s from becoming fragmented.
Unix/Linux “uses a journal instead of writing directly to the disk in sequence. … It will then write the journaled file onto memory and then onto the true disk blocks, but in linear mode.”
In Windows, also, “Solid State Drives DO NOT require defragmentation. It may even decrease the lifespan of the drive.”
Here is a linux command to check the average sequential read speed on your own computer.
First, login as root (su -)
# hdparm -t /dev/sdb2
When running the above benchmark, your disk should be as idle as possible since the advertized speeds and speeds given in reviews will, for consistency, be “otherwise idle”. still, run it several times as it will still vary slightly.
on a desktop 3.5″ 500gig disk I bought in 2009, I got this:
# hdparm -t /dev/sdb2 /dev/sdb2: Timing buffered disk reads: 230 MB in 3.01 seconds = 76.38 MB/sec
# and this, on a desktop 3.5″ 160gig disk I bought in 2005:
# hdparm -t /dev/sda2 /dev/sda2: Timing buffered disk reads: 152 MB in 3.03 seconds = 50.11 MB/sec
sdb2 is my fedora lvm2 partition, sda2 is my ntfs win7 partition.
with 2 runs on my 2010 laptop’s 500gig disk, I got
# hdparm -t /dev/sda6 /dev/sda6: Timing buffered disk reads: 202 MB in 3.01 seconds = 67.16 MB/sec Timing buffered disk reads: 210 MB in 3.00 seconds = 70.00 MB/sec
sda6 is my lvm2 fed13 partition.
Being the 6th partition, (and sda3 being win7 at about 75mb/s), it is out from the highest speeds at the center of the disk.
If you have not downloaded/installed GParted, the partition editor, or “disk utility” (gnome-disk-utilty) you might. They both quickly display a lot of info about your disks and their partitioning. (for instance, that sda6 is my fedora data partition)
The point is, these are real speeds, and for instance, a real SSD read speed of about 250MB/s can be 3 times faster. I am using about 35gb of my win7 partition and about 90gb of my fedora partition (including 50gb of personal photos). I figure I could create a 40gb partition (or smaller) for win7, which I seldom use, remove half my photos, (which I have on other computers anyway) and have the rest of a 120gb SSD for Fedora.
As the individual NAND ICs (the separate memory chips on the SSD) are not especially fast (5-40 MB/second), the controller reads and writes parallel to different chips. Current SSDs have between 4 to 10 channels and so come up to the theoretical speeds that stand in the data sheet.
from a web site review using a new HDD and (250mb/s) SSD
“ATTO benchmark software showed the OCZ had a read time of 244MB/sec and a write time of 172MB/sec. The Seagate HDD had an average read rate of 98MB/sec and a write time of 87MB/sec.
Using HDTach, the read/write results were similar, but different: OCZ’s drive showed a 196MB/sec read rate, the Seagate, 84.6MB/sec.”
in another real world test, “In the Gaming benchmark, the very same SSD in this test, did almost 30% better connected as SATA III and it did with SATA II.”
in Sept. of 2011, there are several SSD’s that claim around 550mb/s read and 500mb/s write speeds.
How to Install an SSD in Your Laptop
To install a new SSD in your notebook and transfer your files over, you will need a Phillips head screwdriver, disk-cloning software, and an external drive enclosure that allows you to connect the SSD to your notebook’s USB port while you’re copying the data. Enclosures start at less than $10 and serve the purpose of both connecting your SSD to the notebook for the initial copy and turning your old hard drive into an external backup disk once it has been removed. For our testing, we used a Zalman ZM-VE200 enclosure ($50.39; www.zalman.com). Our favorite disk cloning software is Acronis Migrate Easy, which typically costs $39.99, but is available as a free demo download for 15 days (www.acronis.com).
First, you must first make sure that your current hard drive does not have more space in use than your new SSD can hold. So, if you have a 120GB SSD and your 320GB hard drive has 150GB of data on it, you will need to delete or copy off, then delete, 30+GB of things.
for a text and photos walk-through of installing an SSD see
* 1. Time For a Change
* 2. Does SSD Deliver?
* 3. The Easy Way
* 4. A Custom Job
* 5. Assemble the Apricorn
* 6. Another Custom Job
* 7. Stop – Copy Time
* 8. Drive Swap I
* 9. Drive Swap II
* 10. Installing the SSD
* 11. Well, That Was Easy
on www.tomsguide.com/us/netbook-upgrade-ssd,review-1481.html
Optimisation
In use you should turn off the automatic defragmentation (for example in Vista), as the defragmentation tools are optimised for HDDs and do more bad than good on SSDs. Some sources also recommend disabling prefetch and superfetch, in order to diminish the access (and therefore the wear).
September 2011 — SSD’s
In early Sept. 2011, Newegg.com is advertizing a 2.5″ 128GB Corsair SSD for $179 which claims a sustained sequential read rate of 550MB/s and a sustained sequential write rate of 515MB/sec.
a buyer made this comment in his review:
using this w/ Linux: make sure you do your research when partitioning/formatting this thing, in order to get the most out of it. I tweaked the EXT4 filesystem quite a bit, and my sequential writes top out at 550mb/s. Sequential reads top at about 500mb/s. Sure, its a chore to get it all set up right under Linux, but believe me, its worth it.