I haven't upgraded that way myself. I've always connected the drives directly to the MB on my computer. Since data throughput is much higher a direct SATA connection is much faster than a USB/SATA or eSATA connection if you're preserving the settings and recordings. However as bciocco and others here have posted, using a USB dual drive docking station does work quite nicely, it just takes a while longer. Since the upgrade doesn't actually clone the drive the heavy lifting would still be handled by the PC's CPU and memory as it runs winMFS or MFSTools. The PC's HDD wouldn't necessarily be active for anything other than running the MFS program (and copying/restoring a truncated backup if you went that direction). Watching the activity in Task Manager (even better Process Explorer) will show you what's going on inside your computer even when the HDD is idle. No, as mentioned above, you're not cloning the drive. Some data is being copied over, but there are a number of other activities (partition changes, expansion, etc.) going on as well. If you were to clone the drive you would end up with the identical recording space, etc. on the new drive...and that would kind of defeat the purpose of upgrading.