Samsung 840 White Paper page 40

frequently perform data searches on their PCs (e.g. business PC users working with Microsoft Outlook or regularly
searching for documents) may benefit from turning this feature ON via the "Advanced" tab in Magician to ensure
optimal system responsiveness. User who do not frequently search for data on their PCs may turn this feature OFF.
Because it generates a significant amount of random read/write activity, this feature is turned OFF for "Maximum
Reliability" mode to reduce SSD writes. It is left on for "Maximum Capacity" mode because the amount of physical space
it uses is negligable and outweighed by the potential user benefit.
Users interested in how much capacity their index file is using may view the hidden "windows.edb" file at:
Windows Vista / 7
C:\ProgramData\Microsoft\Search\Data\Applications\Windows\Windows.edb
Windows XP
C:\Documents and Settings\Application Data\All Users\Microsoft\Search\Data\Applications\Windows\Windows.edb
Prefetch/Superfetch
Windows stores common device drivers and frequently used applications in main memory (DRAM) in order to improve
performance. By disabling these features, the OS can reduce system memory (DRAM) use. Furthermore, since SSDs
have very fast data access times, these features are no longer really necessary. Thus, they are disabled for all profiles.
Write-Cache Buffer
In general, "caching" refers to the pairing of a high-speed storage medium with a lower-speed storage medium to
accelerate overall system performance. Applications or data storage devices (SSDs/HDDs) may send a command to
the Windows OS to temporarily place data in the faster Cache Memory (DRAM on the SSD's or HDD's main board) rather
than directly writing it to the slower permanent storage (NAND chips in the case of SSDs or magnetic platters in the
case of HDDs). In order to maximize both system and SSD performance for Client PCs, Samsung recommends enabling
this feature. If this feature is disabled, there will be significant decrease in Random Read/Write performance. The use of
this feature does not affect the life or capacity of the SSD and is thus enabled for all profiles.
Enabling "Write-Cache" does, however, increase the risk of data loss if the system power fails or the drive is removed
suddenly. This is because DRAM is a volatile storage medium that loses its contents in the absence of power, which
means that data stored in the DRAM cache may not have a chance to be flushed (saved) to storage (NAND) in the event
of sudden power loss.
In general, this is an acceptable risk for Client PC systems because they enjoy a lot of idle time and because SSDs
write data to NAND very quickly. However, for enterprise systems, which typically run under high load 24/7 and place
premium importance upon data integrity and security, this feature is often disabled.
Write-Cache Buffer Flushing
While using the Windows Write-Cache Buffer feature, any data stored in the Cache Memory is lost or damaged in the
event of a device failure or sudden loss of power. The Windows Write-Cache Buffer Flushing feature should be enabled to
ensure data integrity. In particular, this feature is important if your SSD is being used in a server application. When using
an SSD and HDD together, it is always recommended to have this feature ON. Because all configuration profiles use
the "Write-Cache Buffer" feature, this system setting is toggled ON for all profiles. Samsung stronlgy recommens that
Write-Cache Buffer Flushing be enabled at all the times. However, if you are more concered with performance than data
integrity, you are welcome to disable this feature to eliminate extra commands being sent to the SSD to flush the data.
Power Setting Options
Samsung SSDs support DIPM (Device Initiated Power Management). Using this feature, SSDs enter a power saving mode
when they are idle (i.e. when there is no data to read or write). SSDs installed in Home PCs spend most of their time
idle thanks to their extremely fast read and write speeds. Users can manually configure their preferred power setting
options via Windows' "Power Options" dialogue, available via the "Advanced" tab in Magician.
Select either power-saving mode or maximum performance mode, depending on your individual preferences. Laptop
PC users typically choose power-saving mode, while Desktop PC users typically choose maximum performance