Ultrabay data transfer speed?

[trooper09]

Hello,

I am looking at buying a lenovo thinkpad and a dock, the ultrabay. My dock is going to hold a second hard drive, and I am looking at the sata 7200rpm drive.

However, I am not very knowledgeable about using a dock and this will influence my thinkpad laptop purchase. On the surface, it looks like it's a port replicator. Is it different since it locks onto the laptop and uses that latch on the bottom of the laptop? Now, will I be able to achieve the same transfer data rate as I would with an internal hard disk? Or will it be the same data transfer rate as an external USB 2.0 device?

In case you are curious, I am looking at either the Thinkpad X200s, X301 or T400. I want the display port, long battery life, and a light laptop.