Your hard drive is one of the biggest bottlenecks in your PC. We review 10 SSDs to boost your system's performance
Whether you know it or not, odds are that your hard drive is one of the biggest bottlenecks in your PC. These are the last mechanical components of a modern computer, and have managed to hold their own in the face of the rising popularity of Flash memory, thanks to the sheer amount of data that they can store. If you use a Windows 7 PC check your Windows Experience Index, and odds are the lowest score will be your hard drive.
This isn’t a bad thing for most scenarios, but it does heavily contribute to operating system load time and performance. While Flash memory is still too expensive for bulk storage, relatively small capacity Flash has been used for Solid State Drives for some time now, helping to get around the limitations of spinning hard drives.
Large capacity SSDs are financially unviable, when even in its horribly bloated state Windows 7 only uses up around 20GB of space. This means that with some care you can use a low capacity SSD just for Windows and maybe some commonly used programs, which will net you a huge boost in Windows load time and performance.
You’ll need to put your user folders, pagefile and hibernation files onto your hard drive, and watch where you are installing things (games in particular can eat up space rapidly), but once this initial setup is complete you’ll find yourself with a much snappier PC.
We are at an interesting point in the evolution of SSDs. In recent months we have seen the first SATA 6Gbps (also called SATA 3) drives hit the market. These are inherently faster than the SATA 3Gbps (also called SATA 2 – confusing isn’t it?) drives that still dominate the market, but require a modern system to get the most out of them. If you are upgrading an older PC for example, check to see which SATA standards are supported, as there is no point in buying a new SATA 6Gbps SSD if your system will only support the SATA 3Gbps standard.
In this month’s Labs we take a look across the variety of SSDs on the market. Besides both SATA 3Gbps and SATA 6Gbps models of 2.5in SSDs we have included some PCI-Express models and Intel’s new 20GB ‘Larson Creek’ cache drive, which is designed to work with the new Z68 chipset. Keep in mind though that all of these drives vastly outperform mechanical hard drives, so deciding on the right one is a combination of price, performance and your personal needs.
How we tested
Typically, when you look up the technical details of an SSD, the only performance figures you’ll see are maximum sequential read and write speeds. These do give a partial indication of the relative abilities of each drive, but they’re far from the whole story. The graphs opposite show the results of different benchmarks performed by the AS SSD test suite, which we used to test every drive this month. We have also included price per gigabyte results, which as you can see vary quite wildly.
Our next two graphs show random access read and write performance, again as measured by the AS SSD benchmark. The test taxed each drive with reading and writing 4KB blocks in random positions within a 1GB data file. AS SSD has a single-threaded test in which all reads and writes are performed in series, while the multithreaded test launches 64 simultaneous threads of random 4KB reads and writes. It is this 4K-64 thread test that the results are from.
In these tests, SSDs generally fared significantly better than a mechanical hard drive. That’s at least partly thanks to seek times: a mechanical drive must move a physical read/write head into the appropriate position over the platter before it can start to read or write data, incurring a delay of around 5-10ms each time. SSDs, conversely, can address memory cells directly without having to “seek” them first. This enables such drives to start servicing read and write requests within a fraction of a millisecond of receiving them.
But although the SSDs all outclassed mechanical drives, within the group we saw vast variations in performance, especially when it came to writing. Some drives that ranked near the top for sequential performance achieved distinctly more average scores in these tests, while the extra bandwidth available to the hardware RAID based Revodrives push them far out in front.
In our last SSD group test we found some drives simply collapsed in the face of random write requests, yielding average rates of less than 1MB/sec. That’s a big red flag if you’re planning to use an SSD as your system drive, as your operating system is likely to spend more of its time reading and writing odd little files than accessing long streams of data. Thankfully this time around we didn’t encounter that issue, however the lifespan of SSDs means that these older drives may still be found on the market.
We’ve found that poor random access performance is a much greater problem for SSDs than mechanical drives, yielding jerky, stuttering performance in Windows, largely because data writes and reads on SSDs are almost always non-sequential due to the way in which they operate (because there is no spinning disc it doesn’t matter how close one piece of data is to another – it’s the same reason that SSDs don’t need defragmentation like HDDs do).
These issues have become lesser over time though, so you don’t have to worry too much any more that poor random access will kill your performance. More important is choosing the right mix of price and performance for your needs.
View from the labs
This time last year it seemed like SSDs were going to end up everywhere. However it has been quite clear that a lot of the smaller brands trying to get into the market are finding it tough going in the face of the big players. The relationship between controller chip and SSD performance is so intertwined that to compete at the high end companies need access to Sandforce controllers, and while lower spec drives still provide a noticeable performance boost over traditional hard drives, they just don’t compete with the performance of the high end Sandforce models.
Perhaps the biggest change in the SSD market has, however, been the introduction of Intel’s Smart Response technology. This was recently launched as part of the Z68 chipset and it is designed as a compromise between SSD performance and hard drive capacity. Smart Response ties into the SATA controller on the Z68 and lets you use a cache disc. This involves the use of an SSD with a capacity somewhere between 20GB and 60GB combined with a 2TB or less hard drive (we have had difficulty getting it to work with 3TB drives).
Intel’s controller and driver suite then work to use this SSD as a cache. It watches as data is read from the hard drive and makes a copy of the most frequently used data on the SSD. This means that your commonly used files get loaded from the SSD and not the HDD, which boosts performance significantly. Intel quotes in the range of an 80% performance boost, and while it is incredibly hard to accurately benchmark (the adaptive nature of the cache means traditional drive benchmarks don’t work), it does provide a noticeable boost to
It won’t be as fast as using an SSD as a boot drive, but it has the advantages of being relatively cheap (Intel’s SLC flash 20GB drives should sell for around US$110) and hassle-free. Once smart response is set up you need not worry about it again, while commonly used boot drive SSD capacities like 120GB will invariably need watching so they don’t fill up with data.
At the moment only Intel has Smart Response cache drives. This is largely because its careful choice of 20GB-60GB capacity keeps out the majority of drives on the market (most brands start at 64GB). From our conversations with drive manufacturers there is no definite plan as to how they will tackle smart response, but OCZ suggested that it was looking at drives with more overprovisioning designed to work within Intel’s Smart Response envelope.
While we were initially dubious about smart response, our testing has convinced us that it is a great compromise between costs and performance. This is largely because price is still the key aspect to SSD choice. Despite promises that new generation flash technology would drive down costs, they are still quite high (prohibitively so when you get to larger capacities). Smart Response lets us get the capacity we need for day to day use without needing too much messing about.
In a perfect world a boot SSD is still the best performance option, one that is a core part of this Labs editor’s home system. But it does take some fiddling about, and no matter how capacious it sounds, 128GB of space doesn’t last long. But like a lot of things in computing we appreciate that Intel has created a solution that takes the hassle out of the equation without sacrificing too much performance.
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