Crashes with Phase One Rendering

I have been a long time user of this program. And as other folks have not found anything better, so I keep having patience. Anyway, I downloaded my upgrade from EM2 and imported my folder, which is quite big. I kept noticing hang ups and I would have to restart it. I have now changed the rendering to Windows and have started the import process all over again and it is running much faster. Now, I do not have Capture One, I use NX2, and am on a Windows 7 64-bit machine, but if Phase One wanted me to try Capture One, this would not be a good start. I would be curious if more people are having this issue.