Re: What is the fastest way to erase a SATA drive?
You should connect the drive directly to a SATA port on your motherboard. USB could be acting as a bottleneck. If you must use USB, then you should connect it directly to the back of the motherboard's USB port. Do not use a USB hub or other similar device.
In DBAN, just select "Quick Erase" and turn off verification.
I have a Western Digital Elements 2TB External Hard Drive WDBAAU0020HBK connected to the USB port directly on the back of the motherboard. You want the quick erase option because that will only write zeros to your drive and then you want to turn off verification because you don't need to verify. This should reduce the erase time from 5 days to less than 24 hours.
Writing zeros to a 2TB HDD should take less than 24 hours. (For me, it takes ~21 hours with my 2TB HDD on USB.)
BTW, how much did you pay for your 2TB HDD? I bought mine for $50 at Staples on Cyber Monday 2010.