While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Advanced Micro Devices (NASDAQ:AMD) climbed 4% today after Wedbush upgraded the semiconductor company from neutral to outperform.

So what: Along with the upgrade, analyst Betsy Van Hees boosted her price target to $5 per share (from $4), representing about 30% worth of upside to Friday's close. While value investors might be turned off by the stock's big jump in the first half of 2013, Van Hees believes that the growth of new gaming consoles and improving demand in the second half of the year should fuel even further price appreciation.

Now what: Wedbush expects AMD to post Q3 EPS of $0.06 on revenue of $1.42 billion, versus the Wall Street consensus of $0.02 and $1.42 billion. "We believe in the near-term AMD will benefit from the ramp of gaming consoles and a modest lift from 2H seasonality and longer-term is well positioned to gain market share in servers with its dual architecture strategy," noted Wedbush. "We believe AMD is back on track to deliver solid Q/Q and Y/Y earnings and revenue growth and recommend investors with a higher risk/reward tolerance to buy the stock." When you couple the stock's hot run -- up 120% over its 52-week lows -- with AMD's extremely intense competitive environment, I'd definitely agree that a strong stomach is required to jump in.