This isn't necessarily true. The 32-bit version of XP is limited to under 4GB of RAM usage, but NBRCycles may be using a 64-bit version (which can address MUCH more memory). Either way, I would take a look at your memory usage in the task manager. You'll likely find that you're not using anywhere near all 8GB. That much memory for even a video editing application seems quite excessive. Damon, if you're using Windows XP, try the following. Start up your editing software and get it to the point where you notice the preview screen being jerky. Now open up the task manager (ctrl+alt+del), go to the Performance tab. Look at the number called "Physical Memory Total", we'll call this value X. Now look at "Commit Charge Total", we'll call this value Y. If Y > X, you need more RAM If X > Y, the problem is likely that your CPU or graphics card just can't handle the beating you're giving them