Make sure you set the preloading hint slider to a reasonable value (about 1/3 is a good starting point). The issue had to do with the detection of available video memory (which was wrong on some
high-end cards in the 64-bit version) and which affected the program's dynamic resource usage adjustment, causing some images to be unloaded sooner than necessary. In some extreme cases the issue caused the program to disable preloading altogether when GPU acceleration was in effect
Setting the preloading hint slider above about half way may cause the computer to trash (not crash, but crawl helplessly and run far slower then expected) if the images are large and the disks not fast enough. Setting the slider all the way to the right is not
recommended, unless you have an very fast computer and extremely fast disks, like an SAS RAID10, or if all your images are relatively small. If your disks are not able to sustain 300MB/s real world random file I/O, stay away from the far right...