Basically, the 1st problem is that Poser was initially written for the original Mac. Then Ported over to Win 3.1. So you have all the issues that any application had spanning those two very different operating environments. 2nd problem is that Poser was conceived as a virtual artist's woody; so from an architectural standpoint, it was never meant to do a fraction of the things that people try to do with it. 3rd Problem. With Poser 4, the actual hardware people had started having the resources to handle things like multiple figures...but the code base was firmly from the 'old days'. The P4 .bum file is actually a multicolor displacement map, not a grayscale jpg bump map (and ate memory accordingly). 4th problem. The .com collapse. P5 was -supposed- to include a rewrite of the core code, to take advantage of the newer hardware; but it was caught in the implosion, and a lot of things intended never came to be. So while it was tweaked a bit, the memory management system was still the same one from the Mac/Dos/Win era. Meshes were getting denser, skin textures and transmaps were getting larger and larger, more morphs (and a correspondingly larger cr2 file) were being added. For its initial purpose, the memory manager was sufficient. For the purposes it was being put to, a virtual artist studio and animation system, it was showing its age with every passing day. DS is newer code, as is the rendering engine they liscenced. It also doesn't have anywhere near the feature set of P6, and those features slow any app down (if someone ever writes a dynamic cloth and strand based hair plugin for DS, it will impact its performance).