Performance Across Capacities
We all know that SSDs are a surefire way to speed up the rate at which Windows boots up, make applications more responsive, and accelerate large data transfers. But making the move to solid-state storage is an expensive proposition. If you're on a $200 storage budget, you only have two options if you want to incorporate a SSD into your next system build.
- Sink a majority of the cash into a large-enough SSD and spend what's left on a relatively modest hard drive. This lets you drop Windows and a few apps on the SSD and manage your capacity manually. In our opinion, that's the best way to maximize the performance of flash-based storage.
- Spend more on magnetic storage to maximize capacity, then get one of the least-expensive SSDs for a caching-based setup. You can achieve this either with Intel's Z68 Express platform or an add-in card, like the HighPoint RocketHybrid 1220.
|Option 1||Option 2|
|Primary Drive (SSD)||1 x 90 GB OCZ Vertex 2 90 GB||1 x Corsair Nova 32 GB|
|Secondary Drive (Hard Drive)||1 x 250 GB Seagate Barracuda 7200.12||1 x 2 TB WD Caviar Green, 1 x 250 GB Seagate Barracuda 7200.12|
In reality, there's a third option for getting a little flash under your proverbial hood: buy that same small 32 GB SSD, throw Windows and an app or two on it, and simply live with the fact you'll never get to put much more on your SSD, while still managing capacity manually. We don't like that reason very much for a couple of reasons, though.
First, you have to be super-picky about the apps you put on the SSD. It's going to be Windows 7, maybe Microsoft Office, and Photoshop, if you're lucky. And even then, you could run into issues when Windows Update decides to pull a bunch of data onto your boot drive.
Second, smaller MLC-based SSDs tend to shed a lot of performance as they give up capacity. Not to pick on Corsair here, but the 32 GB Nova pushes sustained writes of up to 70 MB/s. The 64 GB version does 130 MB/s. You can apply the same comparison to almost any other vendor, though. Shoot, Intel's drives fare even worse: a 40 GB X25-V is rated for 35 MB/s reads, while an 80 GB X25-M based on the same controller with half as many NAND channels populated pushes that number to 70 MB/s.
Clearly, it appears that the larger the SSD, the more performance you could expect to see from it. That's a really compelling reason to buy the highest-capacity drive you can afford, especially since the cost per gigabyte stays pretty steady as you ascend any given vendor's product lineup.
Now, this presents the hardware press with a conundrum. Vendors prefer sending out their fastest offerings to best represent their respective SSD families. Generally, this means a 256 GB sample. When we review them, we draw generalizations that apply to one capacity specifically. However, it's too easy for a reader to assume the conclusions we draw about one member of a given lineup applies all the way across. And that's simply not the case.
Our point is this: don't expect the same performance out of a smaller SSD just because you saw a higher-capacity model achieving what you want to see in your own system. Though the difference might not always be significant, we want you to have the entire story before making an investment into solid-state technology.
The folks over at Crucial were willing to support our exploration by providing the SSDs we needed to illustrate the difference between drives. The company's new m4 lineup includes 64, 128, 256, and 512 GB models. Take a look at the bottom of the following chart. See how they all hover pretty close to the same price per gigabyte, while sequential write and random write performance trend upward? Those are the spoils available to folks willing to spend more on higher capacities.
We have all four SSDs on-hand and are prepared to show you just how capacity and configuration affects the SSD you end up buying.
|Crucial m4||64 GB||128 GB||256 GB||512 GB|
|Average Access Time||<.1 ms||<.1 ms||<.1 ms||<.1 ms|
|Sequential Read||415 MB/s||415 MB/s||415 MB/s||415 MB/s|
|Sequential Write||95 MB/s||175 MB/s||260 MB/s||260 MB/s|
|4 KB Random Read||40 000 IOPS||40 000 IOPS||40 000 IOPS||40 000 IOPS|
|4 KB Random Write||20 000 IOPS||35 000 IOPS||50 000 IOPS||50 000 IOPS|
|Price On Newegg, As Of 8/1/2011)||$105||$215||$416||$790|