I use Cryo's GPU generator in Direct mode.  Maybe it's just my system but the generator looks like it has crashed for most of the plot creation, there is no progress update.  I just monitor my hard-drives activity.  During this 1st stage there is little to no GPU activity.  After awhile (hours) the GPU kicks in.  The process takes longer than the buffer method but when it is done you have an optimized plot.  Most of my plot files are 500GB optimized and I have a few 1TB optimized plots.  ~16TB all optimized takes about 15sec to process using Luxes Jminer, and this is with the GPU also mining Ether with not noticeable change to Ether mining.

On a side note, My 280X can process the plots in 15 seconds (245MiB/s avg) while the 280 and 390X can only hit 145MiB/s avg.   Not sure why *shrugs*

Good-Luck

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