I'm looking at the ExpressCard as a reasonably fast backup device. I've found Firewire 4* and USB 2.0 to be unacceptably slow. Testing these, the practical throughput rate from disk through the USB or FireWire to the other disk is not even close to theoretically. I know it's a systems issue.

now, does anyone use an ExpressCard SATA 2 interface to talk to an external SATA 2? How well does it work and do you have any reasonable bandwidth numbers? Assume we have a dual core processor.

I use ExpressCard to eSATA and it is as fast as could be expected.

"expected" What does that mean to you? Just curious.

I have a 480Mbps firewire in my laptop, theoretically, I should get something like 40MB/sec transfer rate. It has never even approached that.

I read an article on a guy that used the ExpressCard adapter to connect to two 7200RPM SATA2 external drives. Even with two transfers going, he was able to sustain 65MB/sec per channel across the interface. Assuming I'm backing up a 160GB hard drive, that equates to about 41 minutes - I can live with that.

Expected: eSATA gives you pretty much the same as SATA, which is what most people expect.

fair enough. thanks

The expresscard interface is the same as USB so the data transfer speeds are the same.

What? Oh, no. You are confused. The ExpressCard interface can utilize either PCIe or USB, depending on the card. An expresscard to eSATA should use the PCIe interface providing a theoretical 2.5 Gbps vs USB 2.0's 480 Mbps.

I'm surprised Firewire is slow - I run an external Seagate 750GB off of firewire on my laptop, and get 37MB/s easy.

Expresscard to E-sata should be faster though, if yours isn't performing up to par.

I was mistaken and you are correct in that it supports PCI express OR USB.

Sorry (puts on dunce cap and goes to sit in the corner)

What I was refering to was the limitation of the interface to a single lane and hence the slow speed. The new PCIe 2 interface with XGP sounds tremendously exciting.