Some ASIC stats after playing around with it for a while, can most likely push it a bit further, enjoy.
Once again, this is in no way optimal conditions for the boards, with the heat dissipation surface down.
Can not compare slow corner May/July to early fast corner March/April. If it was fast corner it would be over 1.6T for sure. Is 1300W the limit you discovered by trial (after removing fans)?