8 affordable SSDs, 32 to 64 GB - BeHardware
>> Storage >> SSD

Written by Marc Prieur

Published on September 24, 2010

URL: http://www.behardware.com/art/lire/802/


Page 1

Introduction



While SSDs are an excellent solution for many reasons, thereís still a major sticking point: the price! Sure, since our first article on them in September 2008, things have changed and the price per GB has been halved. Nevertheless, you still need to lay out Ä200 for 80 GB and the only way of reducing this is to go for a lower capacity model!

Of course, you do, at a minimum, need to be able to fit the operating system and the most used applications onto your SSD, otherwise having one is hardly worth it. The minimum number of GBs required will of course vary from one user to another and while 32 GB SSDs are only for those who have really honed their weight down, either because they use an operating system other than Windows or because the applications they use donít take up too much space, a 40 GB model is already much more comfortable and 64 GB will even allow you to install a few games.

The SSDs

For this survey we have selected SSDs under 64 GB that use controllers which have already proved their worth on larger capacity models. They all give a high level of random write performance, at the same time as supporting the TRIM command, which is necessary to maintain a good level of performance over time:

- The Indilinx Barefoot
- The SandForce SF-1200
- The Marvell 88S9174
- The Intel PC29AS21BA0


Page 2
The SSDs

The SSDs, contÖ

The Indilinx Barefoot is used in 3 of the SSDs in this report. Firstly, the Crucial M225 64 GB in a combination which has already proved its worth, namely the Indilinx controller and 45nm Samsung Flash MLC.


The OCZ Onyx 32 and 64 GB stand out for their use of a cut down Barefoot, also called Amigos. The number of channels is halved and it supports a maximum of 8 chips. We were able to open the 32 GB model (as the 64 GB model came from a shop we abstained from doing the same with it). 8 chips of 34nm Intel MLC were used. The 64 GB version would normally be composed in the same way, except for using 8 GB chips rather than 4 GB ones.


Three SSDs are based on the SandForce SF-1200. They are the Corsair F40 and F60 and the OCZ Agility 2 40 GB. They are made up of 34nm Intel MLC, 12x4 GB (48 GB), 16x4 GB (64 GB) and 12x4 GB (48 GB) respectively. While on the 60 GB version 12.6% of the flash is reserved for internal usage, 27.2% is reserved on the 40 GB version. This can be compared to the usual 6.8% with most other SSDs.


The Marvell 88S9174 is only used with the Crucial C300 64 GB. The only SATA 6 Gbits SSD, it gives read speeds of more than 300 MB/s like the larger capacity versions using the same interface. No fewer than 16 x 4 GB 34nm chips made by Micron are used.


Lastly, the Intel PC29AS21BA0 is used in the Intel X25-V 40 GB. With a very simple design, the controller supports just five 34nm 8 GB Intel chips, although in absolute terms it can support Flash on 10 channels.

For the test, we used the same protocol as that used for the larger capacity SSDs.


Page 3
Sequential throughputs

Sequential throughputs
For these speeds, we used IOMeter. This very flexible piece of software allows us among other things to work either with standard data used by most benchmarks and which is easily compressible (series of 0s and 1s), or with random data that canít be compressed. In the first case, SandForceís DuraWrite makes a difference but not in the second, where it has to write and reread almost all the data bit by bit. The random data tests are labelled with an ď/RĒ in the graphs. In practice, the large files that are moved around on a storage device are already compressed (JPEGs, DIVXs, AVC and so on) and so speeds obtained with this random data is in reality the more realistic.


Although small capacity SSDs do pretty well on reads, attaining speeds of up to 125 MB/s for the Onyx 32 GB and 266 MB/s for the Crucial C300 64 GB, the write scores arenít as good. Writes have always been slower on flash and using controllers with fewer channels and/or less dense flash memory has a very visible impact on writes.

Although the Corsair and OCZ SandForces do well with highly compressible data, when the data canít be compressed speeds drop to 70 MB/s on the 40 GB versions and 93.6 MB/s on the 60 GBs. Even worse, weíre at 74 MB/s on the Crucial C300 64 GB, under 65 MB/s on the Onyxs and even as low as 41.9 MB/s on the Intel X40-V! In fact, only the M225 64 GB, combining an Indilinx controller and old 43nm Samsung memory, holds firm.

We should however say that although these figures are low, they arenít terrible: on such a small storage device, you wonít be moving large files around very much, which means that sequential write performance shouldnít be too much of a limitation. Note that with SATA 6 Gbits, the C300 64 GB exceeds 300 MB/s, like the 128 and 256 GB versions. Nevetheless SATA 6 Gbits necessarily implies a Marvell controller and therefore Microsoft drivers for the TRIM command to work, a combination which gives lower performance than SATA 3 Gbits with Intel drivers in the other domains and therefore not necessarily the option to go for.


Staying with sequential accesses, here we tested with small 4 KB blocks. This puts the controller to the test to a maximum in terms of ins / outs. The fastest for reads here is the X25-V 40 GB, while for writes, outside of the SandForces with compressible data, only the old M225 gets away unscathed. Note that the Agility 2 is here a good deal slower than the Corsair F40: this is linked to the fact that the firmware on the Agility 2 limits it to 10,000 IOPS, which isnít the case on the F40 which can go as high as 50,000 IOPS, as can the Vertex 2.


Page 4
Random throughputs

Random throughputs
Random access speeds are where SSDs really mark themselves out from magnetic hard drives, with the ultra-fast SSD access times giving them a big advantage.


While the VelociRaptor struggles here, SSD performance hold firm. The aggressive write combining algorithm means that write speeds are generally higher than reads, with SSDs transforming random writes into sequential writes at the level of the flash in terms of the file allocation table. The notable exception to this rule is with SSDs based on the Indilinx controller as the Onyxs and the M225 therefore give lower random write performance than read. Write levels are however more than sufficient for desktop use and already 10x faster than on the VelociRaptor. With compressible data, the SandForces give the fastest write times, but putting DuraWrite to one side, the C300 does best.

When it comes to random reads, the Crucial C300 and the Indilinx based SSDs are much of a muchness. The SandForces bring up the rear with non-compressible data, with performance levels that are, at worse, 30x better than a VelociRaptor!


Page 5
Random throughputs & NCQ

Random throughputs & NCQ
As on the previous page, here we measure random access performance but with multiple simultaneous accesses. Thanks to NCQ and internal SSD optimisations, the performance levels of some SSDs actually rise in such circumstances, which is typical of heavy usage.


For reads, all the SSDs benefit from NCQ up to 4 simultaneous commands. Beyond this Indilinx-based SSD performance doesnít increase. The C300 gives the best scores.


When it comes to writes, the picture is more complex. With compressible data, the Corsair F40 and F60, which are not limited by their firmware, unlike the Agility 2, perform extremely well but return to normal with non-compressible data. NCQ is then actually counterproductive. In fact, only the X25-V and the C300 give performance gains with concurrent commands, though the gain is limited.


Page 6
File copying

File copying
This brings us to file copying. We measured read and write speeds when copying various groups of files via Robocopy. These groups were composed of:

- A collection of large files: average of 6.8 GB
- Medium-sized files: average of 796 KB
- Small files: average of 44 KB

The source or the target when reading or writing to the drive is a RAID of six 150 GB VelociRaptor drives mounted on an ARECA ARC1280ML PCI-Express x8 card with a strip size of 8 KB. On the VelociRaptor shown in the graph, the files are read and written onto a partition that begins halfway into the drive.


With reads, the C300 does well, whatever the file size. It is followed by the Corsair F60 and X25-V, while the Onyxs bring up the rear.


With writes, the Corsair F60 and M225 64 GB are in pole position. The Onyxs and the X25-V are some way behind.


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Practical tests

Practical tests
After raw performance levels and file copying, we now move on to some slightly more meaningful numbers, the practical tests. While for the other tests, the hard drive was set up as a secondary drive, here it becomes the primary drive. After installing Windows 7 64-bit we time various tasks:

- Windows 7 start-up
We measure how long it takes to start up Windows 7, from initialising the load to the appearance of the Windows desktop.

- Windows 7 start-up + various applications:
This is the time required to start up Windows 7, Adobe Photoshop CS 5, Excel 2010, Word 2010, PowerPoint 2010 and Outlook 2010.

- Launch of a Crysis level:
We measure how long it takes to launch Crysis and a game level launched straight from a command line.

- Installation of Photoshop CS5:
This is the time required to install Photoshop CS5 from the Adobe site download archive to the hard drive. Installation is broken down into two stages, the extraction of files from the archive, then the actual installation.

- Installation of Office 2010:
Here we measure the time required to install Office 2010 from an image on the SSD.


No need for a big SSD to benefit from improved Windows and application launch times! As the scores we got for random reads indicated, these SSDs mirror larger capacity models and give significant improvement in terms of your machineís responsiveness. The Crucial C300 64 GB is slightly faster than the others, but they all give good results.


Here the gains are much lower. In spite of the reduced sequential write speeds, performance levels for the X25-V and the Onyxs arenít catastrophic in this domain, which is after all incidental on low capacity SSDs.


Page 8
Energy consumption

Energy consumption
Here are the energy consumption readings at idle and in load taken for sequential writes in IOMeter:


At idle, SSDs are very economical, in contrast to hard drives on which platters continue to revolve. In load, thereís more of a difference between the various models, but they are all between just 1 and 2 watts


Page 9
Conclusion

Conclusion
The controller should be the number one factor in your choice of SSD and our pre-selection based on our previous tests means that the 8 SSDs reviewed here all offer a very good level of performance. Of course, reducing the number of Flash chips or their density means that sequential write performance is generally a good deal lower than that for larger capacity SSDs, but this is largely incidental when considering lower capacity drives.


When it comes to reads, all these SSDs give very good performance, whether for seqential or random (particularly good) accesses. For random accesses they are even on a par with larger capacity SSDs, which means they can offer comparable applied performance.

What is our advice in terms of capacities? There is only one 32 GB SSD in the survey, the Onyx, and it will be the cheapest. If you canít stretch to anything else, this SSD has no major faults, apart from its capacity of course. Looking at 40 GB, you have the choice between the Intel X25-V and the SandForce SF-1200 (Corsair F40, Agility 2, Vertex 2 and G.Skill Phoenix which are all based on this controller). The SandForce SSDs give better all-round performance, while sequential write speeds for the X25-V are particularly low. Once again, this isnít particularly important, but 42 MB/s is lower than we have seen for some time! On the other hand note that the figures given on product info for the SandForces are for highly-compressible data: when it comes to compressed files, they are far from 220-240 MB/s, scoring closer to 70 MB/s.

For the 60 to 64 GB capacity models, you have the choice between the Indilinx, used on the Onyx 64, the SandForce, on the Corsair F60, and the Marvell, on the Crucial C300. The M225 isnít sold at this capacity. The Onyx 64 is very agressively priced, on a par with the 40 GB models. The Crucial C300 is the most expensive, but gives highest performance. Although the F60 sometimes gives higher write speeds, the C300 gives better read performance and of course this is the most common usage.


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