The T1 needs to be activated by the WINDOWS installer on the initial 128M partition. Once this has been done the full 500GB partition (not GiB partition) will be available for use as exFAT.
I have tested the T1 on Ubuntu 15.04. Sadly it performs closer to a standard platter based HDDs with speeds of 52MB/s when doing a dd between my internal SDD and the T1 in Kubuntu live. I've tried tweaking the bs for dd but no luck :(
While testing with rsync using the exFAT driver in Linux I got speeds closer to 250MB/s still it sucks because I bought the drive for disk cloning using dd and 52MB/s doesn't come close to the 450MB/s advertised.
It appears the drive is optimised for a "tweaked" exFAT format. Possibly proprietory to Samsung? If so I hope the code gets leaked/reverse-engineered for a Linux port soon.
To top it off the cable doesn't fit well in my Lenovo's USB ports for some reason and I am sad to have made this purchase because it does not cater for my needs.