Samsung 840 White Paper page 26

08
Benchmarking Utilities
What You Should Know
With the abundance of Benchmarking Utilities available and the varying results they can report, it can be confusing
to decide which tests to pay attention to and which to question. Sometimes, two blogs using the same tools present
slightly differing results. In fact, there are many variables that can affect test results, including PC configuration and
the options set by the user in the utility itself. Further complicating matters, the results may look cryptic to novices. In
this paper, we will explore some of the most common benchmarking utilities, their configuration options, and how to
interpret some common test results.
Types of Benchmarking Tools
Categories
There are 3 main types of Benchmarking Tools: Synthetic, Trace-Based, and
Application-Based. This paper will explore some of the most common tools,
CrystalDiskMark (CDM), Iometer, PCMark Vantage, and PCMark 7. In addition to
delving into the details of each application, it is also helpful to understand the
wider application categories to which the tools belong.
Synthetic Benchmarking Tools
Some Synthetic Benchmarking tools also allow the user to specify Sequential or Random data access patterns. Randomly
accessed data, as its name suggests, is stored and accessed in a random order (non-neighboring memory locations),
whereas sequentially accessed data is stored and accessed sequentially (in neighboring memory locations). File accessed
randomly are typically small in size (less than 64KB), while files accessed sequentially are usually over 128KB.
Synthetic tests provide the most basic, fundamental information about drive performance, but they do not represent
real-world application performance.
Crystal Disk Mark (CDM)
CrystalDiskMark, freely available via the web, is a very popular storage benchmarking program. Its simple interface
allows the user to specify whether to test sequential or random data, the size of the test range, and the number of
repeat tests. CDM, which Samsung uses when measuring the sequential performance of its SSDs, reports the maximum
sequential and random read/write performance in Megabytes per second (MB/s). Random performance is reported
for three separate workloads: 512KB data, 4KB data at a Queue Depth (QD) of 1, and 4KB data at a QD of 32. The most
important of these are the latter two, as most consumer workloads will be similar to 4KB data at QD 1 and the SSD's
Synthetic Benchmarking Tools mimic the type of stress a drive would experience during
various types of workloads using patterns specifically designed to behave like real-world
processes.
Test data may be either Non-Random (Repeating) or Random (Non-Repeating). Whether the
data is Random or Non-Random may have an effect on SSD performance for some drives
because of differences in controller technology, firmware design, NAND components, and
DRAM cache size and performance. For example, repeating data is compressible, which
means that an SSD that utilizes a compression algorithm will be able to shrink the amount
of data it must actually write to the NAND flash. Samsung SSDs perform equally well with
Repeating and Non-Repeating data because the Samsung MDX controller does not use
compression. Thus, when there is a large discrepancy between competing drives, it is a
good idea to check whether or not the benchmarking utility was sending Random or Non-
Random data and whether or not the tested drives utilize compression.