Linux

Cheers, didn't realise dd could be used for that. Any idea how long it would take for a 1TB drive, I seem to remember it doesn't show progress.

It'll give you a transfer rate. A block size of 1024 works fairly well, but you might want to fiddle with that to get the highest write rate you can.

I usually put it within a for loop and just echo the current value of $i at the beginning of each loop.