KayaNation posted on this board before: "Buy on speculation; Sell on news." AMD just dropped news today about their 3-core processors, so you may have already seen the peak. A good bet at this point is to put a trailing stop on it to protect most of your gain. You can check out your broker's help section on it, but basically, a sell is automatically initiated when the stock price drops so many cents or percentage points from the most current price. You decide how many cents or points you can tolerate losing--lost profit for your case. If the stock goes up, the trailing stop follows it up and only initiates a sell when the price goes back down, beyond the stop threshold. I'm sure other folks have more sophisticated methods, but this exit strategy works for me.
Just be careful if you're still holding next week when the earnings come out. If you think the earnings news will have a negative effect, then sell before then.