All three versions will use more than one core, but LDView only uses multiple cores for transparency sorting (one extra core) and conditional edge line calculations (as many cores as are available). So, under many circumstances, it won't visibly be using all the cores.
Since I don't have access to a dev machine with XP 64, it's very unlikely I'll be able to track down the source of your problem before the official release, but thank you for reporting it. I really do appreciate all bug reports.
Since I don't have access to a dev machine with XP 64, it's very unlikely I'll be able to track down the source of your problem before the official release, but thank you for reporting it. I really do appreciate all bug reports.