Freezing for six seconds every so often?

[oavk]

When I run Diablo III under a second user on my computer, I run into an issue where every so often the game will freeze for six seconds. Timers will continue and I can alt-tab just fine, my computer isn't locked up, it's entirely the game. This only happens when I run it under a second account. The main user can run the game without any issues. Any idea what could be causing this?