Seagate Constellation.2 1TB 2.5-inch SAS RAID Report

The Constellation.2 is back, this time with a SAS interface and three drives for a full on RAID Report.

Published Mon, Jan 24 2011 12:32 AM CST   |   Updated Tue, Nov 3 2020 7:02 PM CST
Manufacturer: Seagate

Introduction, Specifications, Pricing and Availability

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 01 |


Just last week we showed the Seagate Constellation.2 1TB SATA drive. The new Constellation.2 proved to be a worthy successor to the popular Constellation Series and it outperforms the first generation drive by a significant margin. Seagate also managed to double the capacity of the series while keeping the price of the new drives in line with the old offerings.

With the SATA version already under our belt, it is time to focus on the Constellation.2 SAS model. Since most of these drives are configured in RAID arrays, we were given the opportunity to test the new Constellation.2 1TB SAS (Model Number ST91000640SS) in a couple of three drive RAID configurations.

Most users will be building three to five drive RAID 5 arrays in their servers with these drives, so we will do the same. For the performance crowd we will also toss in a three drive RAID 0 array to see just how much performance we can pull from this set of drives.

Before we get too far ahead of ourselves, let's take a look at the specifications for the new Constellation.2 SAS drive.

Specifications, Pricing and Availability

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 02 |

The Constellation.2 is available in three capacity sizes; 250GB, 500GB and 1TB. This is an improvement over last year's models that topped out at 500GB. After you determine the size for your needs, you can then choose between SATA or SAS connectivity. Seagate also offers an encryption option for users requiring additional data security.

The Constellation.2 has a higher platter density than the previous generation and this is what gives the new series higher performance and capacity. The specifications for the new SATA and SAS models look nearly identical. Both use 7,200 RPM spindle speeds, 64MB cache and are the same 15mm height.

The price of SAS connectivity has dropped in recent years and that is very apparent in the new Constellation.2. The 1TB SATA version we reviewed just a few days ago sold for 206.83 at PROVANTAGE. The Constellation.2 1TB SAS model we are looking at today is available from PROVANTAGE for just 243.31. The SAS price premium has dropped considerably and because of this Seagate is expecting the SAS model to outsell the SATA version.

The Seagate Constellation.2 1TB SAS 2.5" HDD

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 01 |

The official name of the new Constellation is actually Constellation.2 (point two). The official model number of the 1TB SAS unit is ST91000640SS, while the 1TB SATA version is designated with an NS on the end.

Here we see the three SAS drives that will be tested in RAID. The front of the drives are labeled with all of the model information and serial numbers.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 03 |

Seagate has moved the surface mount components to the other side of the PCB. There isn't anything to see on this side anymore. All of the standard mounting points are where they should be on the Constellation.2.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 04 |

We should point out that 15mm height drives are not compatible with your notebook; those are 12.5mm height drives.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 05 |

On the back we see that SAS connector which is a little different than SATA. The pins at the top allow for bidirectional communication over twice the number of data points.

Test System Setup and ATTO Baseline Performance

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 07 |

We would like to thank the following companies for supplying and supporting us with our test system hardware and equipment: AVADirect, GIGABYTE, Cooler Master, LSI, Corsair. and Noctua.

You can read more about TweakTown's Storage Product Testing Workstation and the procedures followed to test productsin this article.

Even though we are now into 2011, we plan to use our awesome 2010 test system well into the year. Look for a few updates in the coming weeks as we are starting to make a few changes.

For testing today we are using the ultra fast LSI 9260-8i. Testing was conducted in RAID 0 and RAID 5 on this controller. The single drive (JBOD) tests were ran on an ASUS P6T7 WS SuperComputer motherboard running an onboard Marvell SAS controller without cache.

ATTO Baseline Performance

Version and / or Patch Used:2.34

ATTO is used by many disk manufacturers to determine the read and write speeds that will be presented to customers.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 08 |

The Seagate Constellation.2 reaches full speed at the 128k block range and holds both read and write speeds of around 120MB/s through the rest of the test range. This was a little slower than what we achieved on the SATA model tested on the Intel ICH, but this is due to the controller and not the drive.

Benchmarks - HD Tune Pro

HD Tune Pro

Version and / or Patch Used:4.00
Developer Homepage:
Product Homepage:

HD Tune is a Hard Disk utility which has the following functions:

Benchmark: measures the performance
Info: shows detailed information
Health: checks the health status by using SMART
Error Scan: scans the surface for errors
Temperature display

HD Tune Pro gives us accurate read, write and access time results and for the last couple of years has been gaining popularity amongst reviewers. It is now considered a must have application for storage device testing.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 09 |

In HD Tune we get to see the performance across the drive. The single drive is able to deliver a maximum speed of around 118MB/s, but that dips to 55MB/s at the slowest point on the platters, leaving a 93MB/s average transfer speed. The RAIDed trio does much better; here we see RAID 5 averages 215MB/s and RAID 0 goes up to 268.3MB/s.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 10 |

The write performance is nearly identical to the read performance. Here we see the single drive averaging 92.4MB/s and increasing very well as drives are added to an array.

Benchmarks - Everest Random Access Time

Everest Random Access Time

Version and / or Patch Used:4.60
Developer Homepage:
Product Homepage:

Everest Ultimate and Corporate Edition offer several different benchmarks for testing and optimizing your system or network. The Random Access test is one of very few if not only that will measure hard drives random access times in hundredths of milliseconds as oppose to tens of milliseconds.

Drives with only one or two tests displayed in write the write test mean that they have failed the test and their Maximum and possibly their Average Scores were very high after the cached fills. This usually happens only with controllers manufactured by JMicron.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 11 |

The LSI 9260-8i does a good job of keeping the access times low even when adding up to 8 drives in an array. This wasn't always the case with RAID controllers, as older SCSI RAID controllers use to add latency with each drive added. Here we see that even the RAID array configurations are very close to the latency of a single drive.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 12 |

The write access time has actually decreased with the RAID controller in the data path, since the controller has an onboard cache buffing system.

Benchmarks - Crystal Disk Mark


Version and / or Patch Used:3.0 Technical Preview
Developer Homepage:
Product Homepage:
Download here:

CrystalDiskMark is a disk benchmark software.

Key Features:-

* Sequential reads/writes
* Random 4KB/512KB reads/writes
* Text copy
* Change dialog design
* internationalization (i18n)

Note: Crystal Disk Mark 3.0 is not available to the public yet, but the Technical Preview does allow us to test 4K performance at queue depths of 4 and 32 in addition to 1. The current release Crystal Disk Mark only shows us QD 1.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 13 |

In CMD we are looking at 4k performance and how a drive is able to scale 4k reads at two different native command queuing depths. The single Constellation.2 SAS drive scales very well and the results are then amplified when more drives are added to a RAID array.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 14 |

The write test shows that NCQ doesn't play much of a factor when writing data to the single drive or RAID arrays.

Benchmarks - PCMark Vantage Hard Disk Tests

PCMark Vantage - Hard Disk Tests

Version and / or Patch Used:1.0.0
Developer Homepage:
Product Homepage:
Buy It Here

PCMark Vantage is the first objective hardware performance benchmark for PCs running 32 and 64 bit versions of Microsoft Windows Vista. PCMark Vantage is perfectly suited for benchmarking any type of Microsoft Windows Vista PC from multimedia home entertainment systems and laptops to dedicated workstations and high-end gaming rigs. Regardless of whether the benchmarker is an artist or an IT Professional, PCMark Vantage shows the user where their system soars or falls flat, and how to get the most performance possible out of their hardware. PCMark Vantage is easy enough for even the most casual enthusiast to use yet supports in-depth, professional industry grade testing.

FutureMark has developed a good set of hard disk tests for their PCMark Vantage Suite. Windows users can count on Vantage to show them how a drive will perform in normal day to day usage scenarios. For most users these are the tests that matter since many of the old hat ways to measure performance have become ineffective to measure true Windows performance.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 15 |

HDD1 -Windows Defender
HDD2 - Gaming
HDD3 - Windows Photo Gallery
HDD4 -Vista Startup
HDD5 -Windows Movie Maker
HDD6 -Windows Media Center
HDD7 -Windows Media Player
HDD8 - Application Loading

In a server environment most of these tests will not apply. On desktop computers these are our primary tests. We can still see how much of an improvement the second generation Constellation is over the first generation. The new drive is significantly faster in all tests. Once we get into the RAID arrays, the performance really starts to pick up.

You will notice that two of the results were omitted in the chart. The RAID 5 Media Center results were just over 600MB/s and the RAID 0 were just over 700MB/s. This is caused by the controller's cache system.

Benchmarks - AS SSD

AS SSD Benchmark

Version and / or Patch Used: 1.2.3577.40358
Developer Homepage:Alex Intelligent Software
Product Homepage:Alex Intelligent Software
Download here:

AS determines the performance of Solid State Drives (SSD). The tool contains four synthetic as well as three practice tests. The synthetic tests are to determine the sequential and random read and write performance of the SSD. These tests are carried out without the use of the operating system caches.

In all synthetic tests the test file size is 1GB. AS can also determine the access time of the SSD, the access of which the drive is determined to read through the entire capacity of the SSD (Full Stroke). The write access test is only to be met with a 1 GB big test file. At the end of the tests three values for the read and write as well as the overall performance will be issued. In addition to the calculated values which are shown in MB/s, they are also represented in IO per seconds (IOPS).

Note: AS SSD is a great benchmark for many tests, but since Crystal Disk Mark covers a broader range of 4K tests and HD Tune Pro covering sequential speeds, we will only use the Copy Benchmark from AS SSD.

- Copy Benchmark

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 16 |

The second generation Constellation is quite a bit faster than the first generation and you can see that clearly in the tests where data is read from and written to the same drive. The arrays also scale very well when drives are added.

Benchmarks - Passmark

Passmark Advanced Multi-User Tests

Version and / or Patch Used:6.1
Developer Homepage:
Test Homepage:

Many users complain that I/O Meter is too complicated of a benchmark to replicate results so my quest to find an alternative was started. Passmark has added several multi-user tests that measure a hard drives ability to operate in a multi-user environment.

The tests use different settings to mimic basic multi-user operations as they would play out on your server. Variances is read / write percentage as well as random / sequential reads are common in certain applications, Web Servers read nearly 100% of the time while Database Servers write a small amount of data.

The Workstation test is the only single user environment and will be similar to how you use your system at home.

Seagate Constellation.2 1TB 2.5-inch SAS RAID Report 17 |

Here we see why RAID arrays are so popular in server environments. Performance increases by a significant margin as drives are added. The database test shows this lesson clearly; we went from a single MB/s to over 140 just by joining the drives with a high quality RAID controller.

Final Thoughts

For the past several years Seagate has held a strict timeline for releasing updates to existing product lines. With each update more performance was achieved and less power consumed by the product. The Constellation Series is the higher capacity, lower performance product in the Seagate enterprise line-up. The Savvio (10K RPM) and Cheetah (15K RPM) being the higher performance products of the enterprise line. With the new platter density, the Constellation is actually approaching the same levels of performance of the Savvio.

When looking at the previous generation Constellation, we can see just how much has changed in a year. The new Constellation.2 is quite a bit faster than the first generation drive and even doubles the available capacity. It has been quite a while since we've seen a true doubling of capacity in a single year, but the 2.5" form factor enterprise market has really caught on and manufacturers are looking to produce 2.5" drives with nearly the same capacity as their 3.5" counterparts.

When it comes to pricing, there is still a premium paid for the 2.5" form factor in the original purchase price, but the smaller drives consume less power and over time the additional cost is absorbed by the lower power bill. Another price premium is added when choosing the SAS option, but that is now down to less than 20 USD per drive in the retail market.

The Seagate Constellation.2 1TB SAS HDD is currently available for 243.31 USD. This price is higher than a consumer level drive, but you gain enterprise features and build quality. There aren't very many 1TB 2.5" drives available on the market to begin with, but the Seagate Constellation.2 is the first with this level of features.

What do awards mean? Click for details!

PRICING: You can find products similar to this one for sale below.

USUnited States: Find other tech and computer products like this over at

UKUnited Kingdom: Find other tech and computer products like this over at

AUAustralia: Find other tech and computer products like this over at

CACanada: Find other tech and computer products like this over at

DEDeutschland: Finde andere Technik- und Computerprodukte wie dieses auf

Newsletter Subscription
We openly invite the companies who provide us with review samples / who are mentioned or discussed to express their opinion. If any company representative wishes to respond, we will publish the response here. Please contact us if you wish to respond.
Newsletter Subscription
Latest News
View More News
Latest Reviews
View More Reviews
Latest Articles
View More Articles