Transfer speeds: FW800 to USB3 vs Thunderbolt

On a 2012 IMAC, transferring 500GB from a FW800 drive. The computer doesn't have a FW800 port, so I'm using an adapter that connects via thunderbolt.

Transferring from the FW800 to a USB3 drive took about 2 hours.

Transferring from the FW800 to a thunderbolt drive estimated time is 6 hours?

I thought thunderbolt would be faster than USB3, I'm shocked at the estimated time,
is it that slow because they are using the same thunderbolt bus?

They each have their own port, I'm not daisy chaining.

The estimated time at the start of a large transfer means nothing. Wait a while. If after several minutes the estimated time is much longer than 2 hours you have a problem.

You should not have expected the transfer to the thunderbolt drive to be faster than the transfer to the USB3 drive. They should be about the same, since the bottleneck in each case should be the FW800 drive. The FW800 drive is reading at its best 69 MB/s and the USB3 drive is easily writing at that rate. The FW800 drive would read at its best 69 MB/s and the thunderbolt drive would easily write at that rate.

Your problem, if you have one, is that your thunderbolt drive is unable to write at even 69 MB/s. The thunderbolt connection certainly isn't the problem, since it's rated at over 1000 MB/sec. What's wrong with that thunderbolt drive?

If you have a problem, try a simple experiment. Transfer a large file straight from the IMAC's internal drive to the thunderbolt drive, and time it.

Dennis Couzin
Berlin, Germany

Yeah, I jumped the gun a little bit, it ended up estimating about 2 hours for thunderbolt as well.