eSATA Speeds?


I have an HP HDX18T laptop with an external drive that holds my old stock 250GB/5,400rpm 2.5-inch drive. The external case uses an internal SATA connection and has both a USB 2.0 and eSATA connection externally for my laptop. I’ve read that there is a theoretical transfer rate of 4GB/s with eSATA, but I’m lucky to get 40MB/s copying to or from. Can you tell me what I’m missing? BTW, the external drive case is an Eagle ET-CS2PESU2-BK.

—James Lamar

James, eSATA has a maximum throughput of 3Gb/s. That’s gigabits, though, not gigabytes. So, figure around 300MB/s, less overhead. However, you won’t see many mechanical hard drives actually reach those speeds—the fastest consumer-level hard drives barely get 200MB/s sustained read speeds, and a 250GB/5,400rpm drive doesn’t even approach that. You’re constrained in this case not by the transfer speeds of the eSATA connection, but by the mechanical speed of your hard drive. Especially if you have an older drive, 40MB/s sounds pretty reasonable for a 5,400rpm device. But look on the bright side: It’s still faster than you’ll get using the USB 2.0 interface.

SUBMIT YOUR QUESTION Are flames shooting out of the back of your rig? First, grab a fire extinguisher and douse the flames. Once the pyrotechnic display has fizzled, email the doctor at for advice on how to solve your technological woes.

Around the web