Next generation SSDs and the switch to 25nm

I was awaiting the next generation of SSDs fall 2010, led by Intel. But nothing showed up, so I thought that they maybe waited for CES. But still no new models. Finally Corsair’s Performance 3 Series (using the new Marvel 9174 controller) became available at etailors in Februrary 2011, giving a leap in performance (and price). Rumour has it that Intel will launch their next SSD generation (dubbed the 510 series) in March. AnandTech has a preview of a pre-production sample of OCZ’s new Vertex 3 Pro (using next generation SandForce controller SF-2500). All new models will use SATA III 6Gbps interface, as SATA II 3Gbps would’ve been a bottleneck.

The flash memory used in SSDs has uptil now been produced at 34nm. The switch to 25nm is already in progress. If you have no idea what you just read, it means that the transistors gets smaller and thus one can make more chips of the same silicon, which in turn lowers cost for chipmakers. Corsair’s blog has an excellent Q&A on the topic, from which I borrowed these two:

What is 25nm technology?

25nm technology refers to the feature size of the transistors that are used to make the flash ICs. As the process geometry gets smaller, the capacity of the ICs gets larger, and they become less expensive to manufacture.

How is it different from earlier technologies?

Flash ICs based on 25nm transistors are fairly unique in that the transistors have now become so small that it is starting to become difficult to store a charge on them. Engineers compensate for this by creating very sophisticated error correcting circuits. However, while guaranteeing your data, these transistors create some overhead in terms of capacity and/or performance.

The switch to 25nm allows for using fewer memory chips in a SSD of the same size that a 34nm drive. An example: A 100GB SSD might consists of 10 x 34nm chips, but only 6 x 24nm chips (made up numbers). As a result, the SSD has fewer channels available and since data is written in parallell across these chips, fewer channels equals lower write speed. To make up for this, one can use more 24nm chips of a smaller size, but then the prize also goes up.

So the question is: “Will we get faster and cheaper SSDs?!” The short answer is: “Yes and no.”

Existing models switching to 25nm will neither get faster or cheaper, at least not short term. The next generation though, is going to be a lot faster caused by new controllers coupled with better firmware, but at a premium price.

OCZ has already done the switch to 25nm on their Vertex 2 models (with lower transfer speeds) without telling anybody about it. OCZ has also kept the same productnumbers. This has not fared well with consumers, and after some (bad) press on the matter, OCZ has now taken steps to clean up their act. Corsair on the other hand, is doing a heads-up and telling everybody about their shift to 25nm and that they will distinct these new drives. Read/write speads is on par with current models (I’m talking about the Force series here). The same can be said about Micron/Crucial and the upcoming C400.

Little is known (officially) about Intel’s new drives, but 2011 is certainly going to show some competition in the SSD market.

Worth reading: The State of Solid State 2011 (Tweak Town)

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