In the next CUPS package (1.4.7-2) the priorities will get returned to make the Ghostscript-based gstoraster filter be used instead of the Poppler-based pdftoraster, the pdftops and pstopdf CUPS filters are switched to be Ghostscript-based, and also all Ghostscript calls defined in CUPS are done with "-dNOINTERPOLATE" now. Please test whether everything still works and how much faster it gets.
In the next CUPS package (1.4.7-2) the priorities will get returned to make the Ghostscript-based gstoraster filter be used instead of the Poppler-based pdftoraster, the pdftops and pstopdf CUPS filters are switched to be Ghostscript-based, and also all Ghostscript calls defined in CUPS are done with "-dNOINTERPOLATE" now. Please test whether everything still works and how much faster it gets.