SSD Write Endurance 25nm Vs 34nm

[johnw]

If the 64GB is less than twice as fast as the 32GB it should last more than twice as long

No. If it writes "less than twice as fast" while being double the capacity, it should last LESS than twice as long...assuming it writes faster than the lower capacity model. If both models write at the same speed, then double the capacity should be about double the longevity (although free space and overprovisioning can make a difference).