The confirmation rate per transaction has dropped from over 35,000 per second to 6,000 per second. The logical cost of each tx is essentially the same (and stays constant on the big box). So thrashing is increasing as the cost. If the confirmation rate stayed at the initial 35,000 txs/sec then the full run would have completed in 8.3 hours, but is presently looking like it will be around 18hrs.