I suggest, nay, I recommend that you dispense with screesavers altogether. They are quite unnecessary, consume processor and memory resources and can cause unpredictable behaviour as you have found.
If your graphics card and monitor support Power Management, I recommend that you limit your display management to that. At least you're doing something for the environment by switching off your monitor automatically after, say, 10 minutes or so.
Screensavers were useful once to prevent "burn-in" of a fixed image. Modern monitors don't suffer from this problem.