I just fixed this problem on a friend’s sytem. The culprit was a bad graphics card driver. Try seeing if your graphics card manufacturer has an updated driver. If that doesn’t solve the problem, please let us know what capture decks you used.
I am not familiar with AMD boards, but make sure that it has the SSE2 instruction set. Although, considering the proposed specs, you should be fine, but checking it once again doesn’t hurt.
Did this happen before you installed AspectHD? If not, uninstall AspectHD, download an app called CrapCleaner and clean out your registry entries. Then try to duplicate the problem.
The pre-rendering thing is very annoying and frustrating. I haven’t seen how much processor power it takes, but I will get back to you regarding that later this evening.
I have given up on Canopus. For the first 9 or so months after Premiere Pro 1 was released, they never supported their card efficiently. If you are editing standard DV. you would be better off using a fast system and a firewire card.