Samsung 840 White Paper page 7

mSATA
Building upon the foundations of SATA 3.1, mSATA was designed to address the rising trend of continually shrinking
Notebook computers. Smaller profile laptops require smaller SSDs, which in turn require smaller connectors. Notebooks
that feature the mSATA interface are becoming more popular but still represent a relatively small portion of the overall
market. Maximum transfer speeds are equivalent to the standard SATA 3.0 interface.
SATA Express
SATA Express, once finalized in 2013, will be capable of speeds faster than SATA 6Gb/s thanks to its use of the PCI Express
(PCIe) interface. Interface speeds may be increased to 8Gb/s or 16Gb/s (or perhaps even higher speeds later). Future
motherboards will offer slots for both SATA Express and traditional SATA devices, and the SATA Express interface will be
backward compatible with the standard SATA 3.0 interface.
How SATA Affects SSD Performance
SATA Version
Most SSDs available on the market today are designed for SATA 6Gb/s (SATA 3.x). Many consumers still have older
machines, however, which do not have support for the latest SATA revision. Fortunately, SSDs are backwards compatible
with older SATA versions. They will, however, be limited by the maximum bandwidth supported by the host machine (e.g.
a SATA 6Gb/s SSD connected to a SATA 3Gb/s computer will not be able to reach transfer speeds more than 300MB/s,
even though the drive might be rated for performance well over 500MB/s). This is why it is important to understand the
capabilities of existing PC hardware before upgrading to an SSD – to avoid any potential disappointment if speeds do not
match advertised rates.
Samsung knows that many people still use older computers with SATA 2.0 at home or work, and these people can still
greatly benefit from an SSD upgrade. During its design process, Samsung optimized the 840 Series SSD for maximum
performance on all SATA interfaces, current and legacy. An 840 Series SSD will outperform both an 830 Series (SATA 6Gb/s)
and a 470 Series (SATA 3Gb/s) SSD connected to the same SATA 3Gb/s port, as shown in the table below.
470 (256GB)
830 (256GB)
840 (250GB)
840 PRO (256GB)
* Based on internal test results. Sequential Performance results via CrystalDiskMark. Random Performance results via Iometer 2010.
System Configuration (SATA 3Gbps & 6Gb/s) : Win7 Ultimate x64 SP1 ; Intel Core i7-3770 @3.4Ghz; 4GB DDR3, Intel 7-Series Chipset Z77
In fact, an 840 Series SSD will outperform any SATA 3Gb/s SSD on the market on the same system setup. An investment
in an 840 Series SSD is, therefore, future-proof in that an upgrade now will benefit a SATA 3Gb/s system, but the SSD will
also be ready to offer even better performance in the event that one decides to upgrade to a SATA 6Gb/s system in the
future. Drives designed specifically for an older SATA revision are limited by their aging hardware and will be unable to
saturate the available bandwidth on any SATA interface.
Speaking of computer upgrades, SATA expansion cards are widely available in the market. These cards promise to add
and/or upgrade SATA ports on an existing system. They are limited, however, by a certain amount of overhead and will
often not be capable of providing a modern SSD with the throughput it needs to reach maximum performance. Thus,
Samsung recommends connecting your 840 Series SSD to a native SATA 3.0 (6Gb/s) port to enjoy its full potential.
Locating a native SATA 3.0 (6Gbp/s) port is relatively simple, but it requires some attention to detail. Most motherboards
include both SATA 3.0 and SATA 2.0 ports, and they are often located side-by-
side. While they are usually color-coded, there is no industry standard defining
which color represents which SATA revision. Hence, it is important to carefully
read the labeling to determine which is which.
SATA 3Gb/s Performance Improvements (470 Series as Baseline)
Sequential
Read Write
100% 100%
+4%
+8%
+8%
Read
100%
+0% +52%
-2% +68%
+6% +68%
Random (4KB, Q32)
Write
100%
+95%
+179%
+179%