Overall, the SSD 310 exhibits many of the performance characteristics we have seen from Intel's X25-M. It does come up short in the areas we'd expect, based on the same controller and a more conservative architecture. But we find that perfectly acceptable, given the target customer. Clearly, you can't physically fit ten memory devices onto a form factor this small.
While you mull over our benchmarks, bear in mind that your biggest issue right out of the gate isn't going to be whether you should upgrade to an mSATA-based drive or not. It's going to be finding a device with the requisite slot enabled. That will remain the biggest obstacle for most folks until mSATA-specific slots start becoming much more prevalent.
We want to make it clear that mSATA is not sideways-compatible with miniPCIe, despite their similar edge connectors. You cannot simply drop a mSATA drive into a miniPCIe slot, nor can you do the reverse. Think of mSATA as another miniPCIe mutant. The difference this time is that it's about to become a standard that every notebook vendor should be willing to to follow. Previously, the mutants were more than just vendor-specific. They were model-specific.
Notebook makers do have a choice. They can implement a multiplexer so that a mSATA slot can also function as a miniPCIe slot, but this adds an additional cost to the notebook. Because mSATA drives will usually come preconfigured, dual-purpose slots are likely to be a rare occurrence.
I'm making a big deal about this because Lenovo still lists the Y560, Y560p, and Y460p as all having three miniPCIe slots. This is incorrect. There are two miniPCIe slots and one mSATA slot. A mSATA slot brings the SATA signal straight to the slot. It simply doesn't tie into the PCIe bus without a mux though. At the very least, I'm hoping just that other system vendors don't start confusing miniPCIe with mSATA.
Is a mSATA-based SSD something that you have to have, like a 2.5" SSD was on the desktop when Intel launched its X25-M? That depends on your application. Many decent Arrandale-based Core i5 notebooks cost in the neighborhood of $600-$800. Tacking another $100 to $200 is a hard sell, especially if you're not running the enthusiast-oriented workloads that make an SSD so attractive for your workstation at home.
On the other hand, we've seen how the performance of an SSD helps contribute to efficiency, too, making the SSD 310 a potential battery-saver. At the same time, the device was also created to address environments where the 2.5" form factor simply is not viable. In those applications, an mSATA-based SSD could prove key to enabling plentiful storage at a reasonable performance level.