Calculated yesterday´s image with above DosBox again for testing and comparison. 57508-40 and 41. No difference as you can see. There´s no memory problem either, still free blocks and the memory eater evolution mode works perfectly. BUT !! It´s awfully slow. I set the cpu cycles to max and the priority to highest but caculation time is still some hours instead of 30min with VirtualXP Dosmode. So the SDL platform is not "the yellow of the egg" as we say in Germany. Cannot test Jonathan´s  SDL Fractint as 1280/1024 and the mmods frm do not work as yet, but it´s a bit faster I suppose. Anyway as an alternative or for sound it is ok. Bill, you say MFR calculation stops after some minutes. Please test this Dosbox. If it still happens you may have a cooling problem with your CPU. Clean it and/or get an additional cooler. There still  exist some means to futher speed up performance - increase cpu cycles manually or set a fixed value, which means stress for the CPU of course. I have not changed anymore settings of the config file, maybe there still are some more possible adjustments. Please state if you know any. Thanks. The link is for the DosBox version. ; https://1drv.ms/i/s!AmWYApv7ZBFGgZ0p6k3LIyUm2N4zAA ; Albrecht