The world’s first SSD drive to exceed the SATA II 3 Gbps specification is now available for purchase at Crucial.com.

The Crucial RealSSD C300 comes in 128GB ($499) aand 256GB ($799) models and has been confirmed by third-party websites as being capable of surpassing 350 MB/s read and 200 MB/s write speeds.

HotHardware.com demonstrated that while the C300 can be connected via the SATA II ports common in most user’s current computers and laptops, it’s performance will be capped. In order to get the full performance of the drive, it is necessary to connect it via the new SATA 3.0 6 Gbps controller.

The good news is that if you have a PCI-E x4 expansion slot, you can add a couple of SATA 3.0 ports and 2 USB 3.0 ports to your existing computer in about 60 seconds with a $30 Asus U3S6 PCI-Express SATA 3 6 Gbps / USB 3.0 combo card (warning: Asus only qualifies this card as working with specific Asus motherboards, but I’ve heard others have gotten it working. I just ordered one and will let you know how it turns out. The thing is, this board is not only less expensive than most competing SATA 3 cards, but the inclusion of USB 3.0 doubles its value, especially if you only have one PCI-E x4 or better slot available).

If you don’t have a free PCI-E slot you will probably need a new motherboard for SATA 3, since the PCI-E bus is the only connector your computer has which is capable of providing the bandwidth required.

Crucial has priced the 256GB version of the drive very competitively at $799, pretty much matching the street price for its nearest direct competition, the
OCZ Vertex 250 GB on a price-per-GB basis.

Pricing for the 128GB model is less competitive at $499, putting the cost per GB at nearly $3.89 (vs about $3.12 for the 256 GB version – someone check my math)

As of this writing, the usual suspects – Amazon and NewEgg, did not have a listing for the drive. It will be interesting to see if they discount it at all over the Crucial store.